1 00:00:00,000 --> 00:00:11,100 >> [Halisi kucheza] 2 00:00:11,100 --> 00:00:11,490 >> DAVID J. Malan: zote haki. 3 00:00:11,490 --> 00:00:12,170 Hivyo kuwakaribisha nyuma. 4 00:00:12,170 --> 00:00:15,180 Hii ni CS50, na ni mwisho wa wiki tatu. 5 00:00:15,180 --> 00:00:17,770 >> Hivyo kukumbuka katika kipindi cha wiki kadhaa, tumekuwa kutumia kidogo kabisa ya 6 00:00:17,770 --> 00:00:20,820 wakati juu ya C, juu ya programu, juu ya syntax. 7 00:00:20,820 --> 00:00:24,680 Na ni kawaida kabisa, kama wewe ni bado zinakabiliwa na Tatizo Set 2, kwa kuwa 8 00:00:24,680 --> 00:00:25,950 banging kichwa yako dhidi ya ukuta. 9 00:00:25,950 --> 00:00:28,310 Ni fumbo-kuangalia kosa ujumbe na mende kwamba wewe 10 00:00:28,310 --> 00:00:29,220 hawezi kabisa baada ya chini. 11 00:00:29,220 --> 00:00:32,310 Kwa sababu, mapumziko uhakika kwamba, katika tu muda wiki chache 'itabidi kuangalia nyuma 12 00:00:32,310 --> 00:00:35,930 mambo kama Kaisari, na [? V-genair,]? labda hata Ufa, na 13 00:00:35,930 --> 00:00:40,050 kutambua jinsi mbali umefanya kuja katika kipindi cha muda mfupi. 14 00:00:40,050 --> 00:00:43,670 Hivyo kama kwamba ni faraja yoyote, vumilia kwa sasa. 15 00:00:43,670 --> 00:00:46,610 >> Leo, ingawa, tunaanza mpito mambo ngazi ya juu. 16 00:00:46,610 --> 00:00:49,820 Na sisi kuanza kuchukua nafasi ya kwamba guys kujua jinsi ya mpango, au 17 00:00:49,820 --> 00:00:52,090 angalau mwanzo wa kwamba ngazi ya faraja. 18 00:00:52,090 --> 00:00:56,520 Na tutaweza kuanza kufikiria jinsi gani tunaweza kwenda juu ya kubuni mipango zaidi 19 00:00:56,520 --> 00:00:57,440 kwa ufanisi. 20 00:00:57,440 --> 00:01:01,090 Jinsi gani tunaweza kwenda juu optimizing ufanisi wa algorithms yetu, na 21 00:01:01,090 --> 00:01:03,110 ujumla kutatua zaidi kuvutia matatizo. 22 00:01:03,110 --> 00:01:06,850 Na kuanza kuchukua nafasi ya kwamba, kama sisi alitaka, tunaweza Kanuni up yoyote 23 00:01:06,850 --> 00:01:08,350 mifano ya sisi kuwa na akili. 24 00:01:08,350 --> 00:01:11,430 Hivyo leo, sisi wala kugusa keyboard kwa aina yoyote ya kificho. 25 00:01:11,430 --> 00:01:15,150 Utakuwa ni ngazi ya juu sana, na hatimaye, kuhusu tatizo utatuzi. 26 00:01:15,150 --> 00:01:20,490 >> Hivyo kupata kwa uhakika kwamba, napenda kupendekeza kwamba saba yafuatayo 27 00:01:20,490 --> 00:01:24,290 mistatili kuwakilisha milango saba, nyuma ya ambayo ni rundo zima la 28 00:01:24,290 --> 00:01:26,340 idadi, kati ya ambayo ni idadi 50. 29 00:01:26,340 --> 00:01:30,470 Basi mimi mradi huu juu ya hii screen hapa pia. 30 00:01:30,470 --> 00:01:36,770 Na kupendekeza kwamba tunahitaji mtu wa kujitolea kusaidia kupata mimi namba mbele ya 31 00:01:36,770 --> 00:01:38,140 hisa hapa kuona. 32 00:01:38,140 --> 00:01:40,755 Kuja juu juu, katika pink. 33 00:01:40,755 --> 00:01:43,050 Wote haki. 34 00:01:43,050 --> 00:01:43,930 Nini jina lako? 35 00:01:43,930 --> 00:01:44,850 >> Jennifer: [inaudible] 36 00:01:44,850 --> 00:01:45,170 >> DAVID J. Malan: Samahani? 37 00:01:45,170 --> 00:01:45,860 >> Jennifer: Jennifer. 38 00:01:45,860 --> 00:01:46,390 >> DAVID J. Malan: Jennifer. 39 00:01:46,390 --> 00:01:46,980 Haki zote, Jennifer. 40 00:01:46,980 --> 00:01:47,630 Nice kukutana na wewe. 41 00:01:47,630 --> 00:01:48,370 Kuja juu juu. 42 00:01:48,370 --> 00:01:52,430 Hivyo hawa hapa ni saba milango, na nini Ningependa kufanya kwa sisi hapa, 43 00:01:52,430 --> 00:01:56,560 mbele ya yote ya wanafunzi wako, ni kupata yetu ya simu, 50. 44 00:01:56,560 --> 00:02:00,860 Kupata idadi, unaweza Peek nyuma yoyote ya milango hizi kwa kifupi tapping 45 00:02:00,860 --> 00:02:03,030 kwenye moja ya milango, na ni itaonyesha idadi yake. 46 00:02:03,030 --> 00:02:06,080 Na hebu angalia jinsi ya haraka unaweza kupata sisi simu, 50. 47 00:02:06,080 --> 00:02:09,979 48 00:02:09,979 --> 00:02:11,229 >> 15. 49 00:02:11,229 --> 00:02:13,110 50 00:02:13,110 --> 00:02:14,360 16. 51 00:02:14,360 --> 00:02:16,270 52 00:02:16,270 --> 00:02:16,530 50. 53 00:02:16,530 --> 00:02:17,350 Nicely kufanyika. 54 00:02:17,350 --> 00:02:18,040 Wote haki. 55 00:02:18,040 --> 00:02:19,906 Raundi ya applause kwa Jennifer. 56 00:02:19,906 --> 00:02:21,530 >> [Makofi] 57 00:02:21,530 --> 00:02:22,320 >> Wote haki. 58 00:02:22,320 --> 00:02:25,254 Hivyo kile alikuwa mkakati wako kwa kutafuta posta, 50? 59 00:02:25,254 --> 00:02:27,222 >> Jennifer: Um, nilifikiri labda kama - 60 00:02:27,222 --> 00:02:27,714 [Inaudible] 61 00:02:27,714 --> 00:02:28,206 >> DAVID J. Malan: Oh. 62 00:02:28,206 --> 00:02:29,630 Kutoa ni moja ya pili. 63 00:02:29,630 --> 00:02:32,420 Hivyo alikuwa mkakati wako kwa kutafuta posta, 50? 64 00:02:32,420 --> 00:02:34,760 >> Jennifer: Kwa hiyo mimi tu kuanza saa mwanzo kuona nini idadi ya kwanza 65 00:02:34,760 --> 00:02:38,590 mara, na kisha mimi mawazo, labda kama wao ni Iliyopangwa, Mimi nitaendelea 66 00:02:38,590 --> 00:02:39,970 tapping juu juu? 67 00:02:39,970 --> 00:02:40,140 >> DAVID J. Malan: OK. 68 00:02:40,140 --> 00:02:42,910 Na sisi wanaonekana kuwa kupatikana kwamba kuwa kesi. 69 00:02:42,910 --> 00:02:45,670 Ingawa, hebu peel nyuma tabaka kidogo tu, na wewe unataka kwenda 70 00:02:45,670 --> 00:02:47,640 mbele na yatangaza milango mengine unaweza kuwa waliochaguliwa? 71 00:02:47,640 --> 00:02:50,400 72 00:02:50,400 --> 00:02:51,712 >> Jennifer: Oh, dear. 73 00:02:51,712 --> 00:02:53,128 >> DAVID J. Malan: Ah. 74 00:02:53,128 --> 00:02:54,280 >> Jennifer: Kwa hiyo mimi tu got bahati. 75 00:02:54,280 --> 00:02:55,270 >> DAVID J. Malan: Hivyo wewe got bahati. 76 00:02:55,270 --> 00:02:55,710 Wote haki. 77 00:02:55,710 --> 00:02:56,795 Hivyo si mbaya. 78 00:02:56,795 --> 00:02:58,750 Lakini hiyo ni ya kuvutia ufahamu, sawa? 79 00:02:58,750 --> 00:03:01,870 Kama wewe kudhani, na wewe alifanya kupata, kweli, kidogo bahati huko. 80 00:03:01,870 --> 00:03:05,350 Lakini kama wewe kudhani kuwa idadi walikuwa Iliyopangwa, unaweza kuwa sahihi zaidi 81 00:03:05,350 --> 00:03:08,750 kama jinsi kwamba kusukumwa tabia yako? 82 00:03:08,750 --> 00:03:11,715 >> Jennifer: Hivyo kama walikuwa Iliyopangwa, mimi walidhani labda wadogo na ukubwa. 83 00:03:11,715 --> 00:03:11,970 >> DAVID J. Malan: OK. 84 00:03:11,970 --> 00:03:15,260 >> Jennifer: Au kama hii kuishia kuwa kubwa kweli kweli, basi kubwa kwa madogo. 85 00:03:15,260 --> 00:03:15,540 >> DAVID J. Malan: OK. 86 00:03:15,540 --> 00:03:18,170 Hivyo kubwa kwa wadogo, au wadogo na ukubwa. 87 00:03:18,170 --> 00:03:21,990 Lakini basi mimi kupendekeza, tuseme wewe alikuwa waliopata bahati, na kudhani kuwa wao 88 00:03:21,990 --> 00:03:26,840 walikuwa si, kwa kweli, namna, jinsi wengi wale milango gani unaweza kuwa alikuwa na Peek 89 00:03:26,840 --> 00:03:28,590 nyuma katika kesi hiyo mbaya? 90 00:03:28,590 --> 00:03:29,860 >> Jennifer: Wote. 91 00:03:29,860 --> 00:03:30,420 >> DAVID J. Malan: Wote. 92 00:03:30,420 --> 00:03:31,740 Basi hebu generalize kwamba kama n. 93 00:03:31,740 --> 00:03:34,790 Kuna hutokea kwa kuwa 7, lakini hebu zaidi ujumla kusema kuna milango n juu ya 94 00:03:34,790 --> 00:03:35,650 screen hapa. 95 00:03:35,650 --> 00:03:40,110 Hivyo katika hali mbaya zaidi, ingekuwa kuangalia nyuma ya milango 7, au milango n. 96 00:03:40,110 --> 00:03:44,140 Na hivyo hii ni kweli, ni kidogo ya bahati leo, lakini ni kweli linear 97 00:03:44,140 --> 00:03:46,440 algorithm ya kila aina, hata kama wewe walikuwa aina ya kuruka karibu. 98 00:03:46,440 --> 00:03:47,080 Ni haki hiyo? 99 00:03:47,080 --> 00:03:47,500 >> Jennifer: Yeah. 100 00:03:47,500 --> 00:03:50,000 >> DAVID J. Malan: Naam, napenda kuona kama yako mkakati wa mabadiliko kama mimi hoja yetu 101 00:03:50,000 --> 00:03:52,190 mfano wa pili yetu hapa na 7 mbalimbali milango. 102 00:03:52,190 --> 00:03:55,240 Huo idadi, lakini hii wakati wao ni Iliyopangwa. 103 00:03:55,240 --> 00:03:58,350 Nini mkakati wako hapa kwenda kuwa, kujaribu kuweka nje ya akili yako nini 104 00:03:58,350 --> 00:03:59,310 idadi nyingine walikuwa - 105 00:03:59,310 --> 00:03:59,930 >> Jennifer: OK. 106 00:03:59,930 --> 00:04:02,290 >> DAVID J. Malan: - mapema? 107 00:04:02,290 --> 00:04:03,180 >> Jennifer: Hebu kuanza na moja ya kwanza. 108 00:04:03,180 --> 00:04:03,540 >> DAVID J. Malan: zote haki. 109 00:04:03,540 --> 00:04:05,190 Kuanza na moja ya kwanza. 110 00:04:05,190 --> 00:04:05,960 4. 111 00:04:05,960 --> 00:04:08,810 Sasa ambapo wewe kwenda, na kwa nini? 112 00:04:08,810 --> 00:04:10,040 >> Jennifer: 4 kwa kweli ni ndogo. 113 00:04:10,040 --> 00:04:12,500 Hivyo kama wao ni aina ndogo labda kwa ukubwa, ni lazima 114 00:04:12,500 --> 00:04:13,290 kuwa mara mbili kwamba, na -. 115 00:04:13,290 --> 00:04:13,670 >> DAVID J. Malan: OK. 116 00:04:13,670 --> 00:04:15,990 Hebu angalia, ambayo unafikiri? 117 00:04:15,990 --> 00:04:19,050 >> Jennifer: Jaribu moja ya mwisho. 118 00:04:19,050 --> 00:04:19,500 Nice. 119 00:04:19,500 --> 00:04:20,880 >> DAVID J. Malan: Sana nicely kufanyika. 120 00:04:20,880 --> 00:04:21,860 Wote haki. 121 00:04:21,860 --> 00:04:23,010 >> [Makofi] 122 00:04:23,010 --> 00:04:24,310 >> DAVID J. Malan: OK. 123 00:04:24,310 --> 00:04:26,790 Hivyo wewe ni kweli kufanya hii horribly, kwa sababu wewe ni 124 00:04:26,790 --> 00:04:27,700 kufanya vizuri sana. 125 00:04:27,700 --> 00:04:31,150 Ambazo zinatuacha hawawezi kufanya pointi fulani. 126 00:04:31,150 --> 00:04:32,565 Basi hebu jaribu nirudishe hapa. 127 00:04:32,565 --> 00:04:34,560 >> Jennifer: OK. 128 00:04:34,560 --> 00:04:35,980 >> DAVID J. Malan: Ni vizuri kufanyika, hata hivyo. 129 00:04:35,980 --> 00:04:39,060 Hivyo ilianza mwanzoni, wewe akaona ya kuwa ni 4, basi 130 00:04:39,060 --> 00:04:40,240 wakiongozwa na mwisho. 131 00:04:40,240 --> 00:04:42,320 Lakini tuseme wewe si kupata bahati huko, na kudhani 50 132 00:04:42,320 --> 00:04:42,890 Ilikuwa mahali pengine. 133 00:04:42,890 --> 00:04:46,190 Nini hatua yako ya tatu wamekuwa? 134 00:04:46,190 --> 00:04:47,680 >> Jennifer: Nenda nyuma mwanzo. 135 00:04:47,680 --> 00:04:48,320 >> DAVID J. Malan: Nenda nyuma ya mwanzo. 136 00:04:48,320 --> 00:04:51,320 OK, hivyo ungependa wameweza kuguswa mlango huu, ambayo ilikuwa 8. 137 00:04:51,320 --> 00:04:51,660 Wote haki. 138 00:04:51,660 --> 00:04:52,650 Hivyo si kwamba 50. 139 00:04:52,650 --> 00:04:55,380 Ambapo ingekuwa wewe inaonekana ijayo? 140 00:04:55,380 --> 00:04:56,720 >> Jennifer: Kama mimi si kujua wao Iliyopangwa. 141 00:04:56,720 --> 00:04:57,005 >> DAVID J. Malan: Sahihi. 142 00:04:57,005 --> 00:04:58,490 Naam, kama alivyofanya kujua wao walikuwa Iliyopangwa - 143 00:04:58,490 --> 00:04:58,700 >> Jennifer: Oh, je, kujua, yeah. 144 00:04:58,700 --> 00:05:00,910 >> DAVID J. Malan: - lakini hakuwa kujua ambapo 50 alikuwa bado? 145 00:05:00,910 --> 00:05:01,785 >> Jennifer: Tu kuendelea. 146 00:05:01,785 --> 00:05:02,130 >> DAVID J. Malan: zote haki. 147 00:05:02,130 --> 00:05:02,520 OK. 148 00:05:02,520 --> 00:05:03,800 Kuendelea. 149 00:05:03,800 --> 00:05:05,270 OK, kwamba siwezi kufanya kazi pamoja. 150 00:05:05,270 --> 00:05:05,610 >> Jennifer: OK. 151 00:05:05,610 --> 00:05:07,210 >> DAVID J. Malan: Sasa, kama wewe tu kwenda kuweka kwenda, nini yako 152 00:05:07,210 --> 00:05:09,680 algorithm kukabidhi yanayoambatana ndani. 153 00:05:09,680 --> 00:05:10,740 >> Jennifer: linear -. 154 00:05:10,740 --> 00:05:11,820 >> DAVID J. Malan: Ni aina ya linear. 155 00:05:11,820 --> 00:05:13,480 Lakini basi mimi kupendekeza, basi mimi kuweka papo hapo. 156 00:05:13,480 --> 00:05:14,900 Hebu furahisha ukurasa. 157 00:05:14,900 --> 00:05:17,120 huo idadi, huo mpangilio, huo milango. 158 00:05:17,120 --> 00:05:21,350 Lakini kufikiri nyuma ya siku hiyo ya kwanza katika darasani wakati sisi akararua kitabu cha simu katika 159 00:05:21,350 --> 00:05:25,480 nusu, aina ya, na nini ilikuwa mkakati wetu huko? 160 00:05:25,480 --> 00:05:26,450 >> Jennifer: Kuanza katika katikati. 161 00:05:26,450 --> 00:05:26,690 >> DAVID J. Malan: OK. 162 00:05:26,690 --> 00:05:27,610 Hivyo kuanza katikati. 163 00:05:27,610 --> 00:05:28,790 Basi hebu kwenda mbele na kuiga hiyo. 164 00:05:28,790 --> 00:05:30,720 Kuanza saa katikati na akifafanua kuwa mlango. 165 00:05:30,720 --> 00:05:31,660 Hivyo namba 16. 166 00:05:31,660 --> 00:05:35,290 Hivyo gani guy nguvu wamefanya, ambao akararua kitabu cha simu katika nusu, 167 00:05:35,290 --> 00:05:38,450 kupata nadhani ijayo? 168 00:05:38,450 --> 00:05:39,400 >> Jennifer: Nenda katika nusu hii. 169 00:05:39,400 --> 00:05:41,700 >> DAVID J. Malan: Na kwa nini upande wa kulia? 170 00:05:41,700 --> 00:05:43,900 >> Jennifer: Kama walikuwa aina ya ndogo na ukubwa, basi 50 lazima 171 00:05:43,900 --> 00:05:44,720 mwishoni kwamba. 172 00:05:44,720 --> 00:05:44,920 >> DAVID J. Malan: Good. 173 00:05:44,920 --> 00:05:45,390 Kabisa nafuu. 174 00:05:45,390 --> 00:05:48,380 Hivyo kama kitabu cha simu, unaweza kwenda kulia kinyume na kushoto, lakini hapa 175 00:05:48,380 --> 00:05:49,500 ni takeaway muhimu. 176 00:05:49,500 --> 00:05:53,930 Wewe sasa unaweza kutupa mbali, au chozi mbali, nusu ya tatizo hili, na kuacha wewe si 177 00:05:53,930 --> 00:05:55,970 na 7 milango, lakini kwa kweli na 3 tu. 178 00:05:55,970 --> 00:05:57,870 Ambayo ni takribani nusu ya ukubwa wa tatizo. 179 00:05:57,870 --> 00:05:58,350 Wote haki. 180 00:05:58,350 --> 00:06:01,890 Hivyo sasa nini ungependa kuwa kufanyika baada ya wewe kwenda haki? 181 00:06:01,890 --> 00:06:05,870 >> Jennifer: Hivyo 16 bado ni pretty ndogo, jamaa na 50, hivyo labda nitajaribu 182 00:06:05,870 --> 00:06:06,700 kama, hii moja. 183 00:06:06,700 --> 00:06:07,890 >> DAVID J. Malan: zote haki. 184 00:06:07,890 --> 00:06:08,720 42. 185 00:06:08,720 --> 00:06:10,830 Haki ya wote, hivyo sasa nini yako silika kuambia wewe? 186 00:06:10,830 --> 00:06:12,100 >> Jennifer: Siwezi kutupa hii na kisha tu - 187 00:06:12,100 --> 00:06:12,360 >> DAVID J. Malan: OK. 188 00:06:12,360 --> 00:06:14,212 Nzuri, unaweza kutupa mbali nusu ya kushoto huko. 189 00:06:14,212 --> 00:06:14,890 >> Jennifer: - pick hii moja. 190 00:06:14,890 --> 00:06:15,530 >> DAVID J. Malan: Na haki. 191 00:06:15,530 --> 00:06:15,760 >> Jennifer: Yeah. 192 00:06:15,760 --> 00:06:17,820 >> DAVID J. Malan: Hivyo hata kama ni ngumu kuona pengine, wakati kuna tu 193 00:06:17,820 --> 00:06:21,320 7 milango, kufikiri juu, sasa, msimamo wa 194 00:06:21,320 --> 00:06:22,620 algorithm wewe tu kutumiwa. 195 00:06:22,620 --> 00:06:24,510 Katika kesi ya awali, alifanya kupata bahati, ambayo ilikuwa kubwa. 196 00:06:24,510 --> 00:06:26,540 Lakini wewe alifanya kutumia heuristic, Ningependa kusema. 197 00:06:26,540 --> 00:06:29,150 Unaweza kutumika aina ya silika yako, na kujua namna, kama ni pretty 198 00:06:29,150 --> 00:06:31,600 ndogo katika mwanzo, ni wazi, tumekuwa got kwenda zaidi ya kulia. 199 00:06:31,600 --> 00:06:34,990 Lakini katika baadhi ya hisia, wewe got bahati, sababu labda hii ilikuwa namba 100, 200 00:06:34,990 --> 00:06:36,220 na labda 50 ilikuwa zaidi katikati. 201 00:06:36,220 --> 00:06:37,910 Labda 50 alikuwa hata zaidi ya hapa. 202 00:06:37,910 --> 00:06:40,960 >> Lakini nini alifanya tofauti kidogo wakati huu, wewe waliwafanyia 203 00:06:40,960 --> 00:06:42,150 tena na tena. 204 00:06:42,150 --> 00:06:45,310 Na napenda kusema kwamba nini tu gani, pamoja na kusukumwa na simu 205 00:06:45,310 --> 00:06:48,100 kitabu mfano, ni kitu gani zaidi algorithmic, na mengi 206 00:06:48,100 --> 00:06:49,930 chini maalum cased. 207 00:06:49,930 --> 00:06:51,620 Kiasi kidogo kisilika. 208 00:06:51,620 --> 00:06:57,160 Hivyo katika mwisho wa siku, jinsi gani unaweza kuelezea ufanisi wa 209 00:06:57,160 --> 00:07:00,530 kwanza algorithm, ambapo walikwenda kushoto na kulia, dhidi ya 210 00:07:00,530 --> 00:07:03,430 pili algorithm hapa? 211 00:07:03,430 --> 00:07:06,460 >> Jennifer: Hii moja lazima, kama, labda kupunguza nusu ya muda, au hata zaidi, yeah. 212 00:07:06,460 --> 00:07:07,320 >> DAVID J. Malan: Sawa, labda hata zaidi. 213 00:07:07,320 --> 00:07:10,150 Hebu kushinikiza vigumu kidogo juu ya hilo. 214 00:07:10,150 --> 00:07:13,030 Nini kweli, kama sisi kuendelea hii mantiki, sisi dhahiri nusu 215 00:07:13,030 --> 00:07:15,830 mbio wakati na algorithm hii ya pili kwa kutupa mbali nusu ya 216 00:07:15,830 --> 00:07:18,470 idadi, lakini nini sisi kufanya juu ijayo iteration, wakati Jennifer umebaini 217 00:07:18,470 --> 00:07:20,615 idadi ya pili? 218 00:07:20,615 --> 00:07:22,830 >> Sisi nusu idadi ya milango tena. 219 00:07:22,830 --> 00:07:25,270 Na kisha nini sisi kufanya baada ya kuwa, kama kulikuwa na zaidi ya milango ya kucheza na? 220 00:07:25,270 --> 00:07:27,520 Tunataka kupunguza nusu yao, na tena, na tena, na tena. 221 00:07:27,520 --> 00:07:30,420 Na hii ilikuwa tu kama nyie wote alisimama katika wiki ya kwanza ya 222 00:07:30,420 --> 00:07:33,000 darasa, nusu ya wewe kukaa chini, nusu ya wewe kukaa chini, nusu ya wewe 223 00:07:33,000 --> 00:07:35,440 kukaa chini, mpaka mmoja lone nafsi alikuwa amesimama. 224 00:07:35,440 --> 00:07:39,050 Na sisi alisema kwamba wakati mbio ya kwamba, idadi ya hatua ilichukua mara 225 00:07:39,050 --> 00:07:40,430 juu ya utaratibu wa nini? 226 00:07:40,430 --> 00:07:41,230 >> SPIKA 1: [inaudible] 227 00:07:41,230 --> 00:07:43,970 >> DAVID J. Malan: Hivyo logi msingi ya 2 ya n, au tu zaidi tu, ingia ya n. 228 00:07:43,970 --> 00:07:45,060 Hivyo kitu logarithmic. 229 00:07:45,060 --> 00:07:48,380 Na graph hakuwa mstari moja kwa moja kwamba tu got mbaya zaidi na zaidi, ilikuwa ni 230 00:07:48,380 --> 00:07:52,490 hii Curve kuvutia kwamba hakuwa kupata hivyo mbaya baada ya muda. 231 00:07:52,490 --> 00:07:53,910 Basi hebu kushikilia wazo hili. 232 00:07:53,910 --> 00:07:54,690 Hebu kuwashukuru Jennifer. 233 00:07:54,690 --> 00:07:56,150 Asante sana kwa kuja juu juu. 234 00:07:56,150 --> 00:07:57,400 Na, moja sec. 235 00:07:57,400 --> 00:08:00,170 236 00:08:00,170 --> 00:08:02,925 Taa dawati hakuna leo, lakini sisi kufanya kuwa mipira ya dhiki CS50. 237 00:08:02,925 --> 00:08:03,420 >> Jennifer: Yay. 238 00:08:03,420 --> 00:08:04,410 >> DAVID J. Malan: zote haki, hapa. 239 00:08:04,410 --> 00:08:06,545 Asante kwa incurring mkazo hapa juu. 240 00:08:06,545 --> 00:08:07,350 Wote haki. 241 00:08:07,350 --> 00:08:10,620 Basi hebu angalia kama hatuwezi sasa kurasimisha hii kidogo zaidi. 242 00:08:10,620 --> 00:08:14,820 Hivyo tena, nini sisi tu alifanya alikuwa kimsingi kitu sawa kama tulivyofanya 243 00:08:14,820 --> 00:08:16,660 kwa kuwa wiki ya kwanza. 244 00:08:16,660 --> 00:08:23,780 Lakini badala ya mwisho na tu linear algorithm, ambayo sisi taswira 245 00:08:23,780 --> 00:08:27,210 hapo awali kama mstari huu moja kwa moja, ambapo, kama sisi kuweka moja zaidi juu ya mlango 246 00:08:27,210 --> 00:08:29,610 screen, basi ingekuwa Jennifer wamekuwa na kuangalia, uwezekano, 247 00:08:29,610 --> 00:08:30,600 nyuma ya mlango mmoja zaidi. 248 00:08:30,600 --> 00:08:33,490 Kama sisi kuweka milango miwili zaidi, yeye anaweza kuwa na kuangalia nyuma ya milango miwili zaidi. 249 00:08:33,490 --> 00:08:35,990 >> Na hivyo, kulikuwa na linear uhusiano kati ya ukubwa wa 250 00:08:35,990 --> 00:08:39,059 tatizo juu, kusema, mhimili x-, na kiasi cha muda inachukua 251 00:08:39,059 --> 00:08:40,440 kutatua juu y. 252 00:08:40,440 --> 00:08:43,330 Lakini picha nilikuwa akidokeza mwanzoni ilikuwa line hii ya kijani. 253 00:08:43,330 --> 00:08:45,970 Kijani kwa makusudi, kwa sababu tu waliona bora. 254 00:08:45,970 --> 00:08:49,790 Katika nadharia, algorithm, wakati sisi alifanya hivyo na kitabu cha simu, wakati sisi alifanya hivyo 255 00:08:49,790 --> 00:08:52,420 na wewe guys kuhesabu kila mmoja, na katika kesi ya pili, wakati Jennifer tu 256 00:08:52,420 --> 00:08:55,250 alifanya hivyo hapa juu, ilikuwa ni aina ya kimsingi zaidi. 257 00:08:55,250 --> 00:08:57,180 Kwa sababu haikuwa tu mara mbili kwa haraka. 258 00:08:57,180 --> 00:08:58,870 Haikuwa hata mara nne kwa haraka. 259 00:08:58,870 --> 00:09:03,290 Ilikuwa hutegemea nini ukubwa wa pembejeo ilikuwa, kama jinsi wengi 260 00:09:03,290 --> 00:09:05,220 hatua hatimaye alichukua. 261 00:09:05,220 --> 00:09:08,040 >> Na hivyo hii wazo rahisi kwamba sisi wote alichukua kwa nafasi na kitabu cha simu, 262 00:09:08,040 --> 00:09:10,200 unaweza vile vile kutumika kwa kitu kama hiki. 263 00:09:10,200 --> 00:09:12,380 Na hii inaweza kuwa zaidi ya kawaida inayojulikana kama, kama waweza 264 00:09:12,380 --> 00:09:13,940 kufikiria, kugawanya na kushinda. 265 00:09:13,940 --> 00:09:16,390 Si tofauti na kile sisi alivyofanya, bila shaka, na kitabu cha simu. 266 00:09:16,390 --> 00:09:18,300 >> Lakini pseudocode, kukumbuka, ilikuwa hii. 267 00:09:18,300 --> 00:09:21,800 Hivyo sisi si kufanya hii tena, lakini kukumbuka kwamba wiki ya kwanza, sisi wote walisimama 268 00:09:21,800 --> 00:09:25,140 na kisha nusu ya wewe ameketi chini, nusu ya wewe ameketi chini, nusu ya wewe kukaa chini. 269 00:09:25,140 --> 00:09:29,280 Kwamba algorithm ilikuwa kutekelezwa katika kidogo ya njia cheating, kwa kuwa, ni 270 00:09:29,280 --> 00:09:32,870 ilikuwa moja tu ya mimi kuhesabu, kimsingi, kwa ufanisi zaidi. 271 00:09:32,870 --> 00:09:35,830 Katika kesi hiyo, nilikuwa leveraging rasilimali ya sekondari. 272 00:09:35,830 --> 00:09:39,470 Aina ya, CPUs nyingi, nyingi akili, nyingi watu smart katika 273 00:09:39,470 --> 00:09:42,740 chumba walikuwa kusaidia mimi kupata kutoka kitu linear kitu 274 00:09:42,740 --> 00:09:45,190 logarithmic, kutoka kitu nyekundu na kijani kitu. 275 00:09:45,190 --> 00:09:48,650 >> Lakini katika kesi hii, Jennifer peke yake anaweza kimsingi kuboresha juu ya 276 00:09:48,650 --> 00:09:52,370 utendaji wa algorithm yake ya kwanza na, tena, tu kufikiri vigumu kidogo. 277 00:09:52,370 --> 00:09:56,650 Na sasa, linapokuja wakati wa kutekeleza mambo haya, kuhesabia 278 00:09:56,650 --> 00:10:00,670 nini mstari wa kanuni unaweza kuandika vile kwamba unaweza kurudia tena, na 279 00:10:00,670 --> 00:10:03,350 tena, na tena, aina ya kwa mtindo looping. 280 00:10:03,350 --> 00:10:06,370 Kwa sababu wewe si kwenda kuwa na anasa, kama alivyofanya Jennifer mara ya kwanza, kwa 281 00:10:06,370 --> 00:10:10,460 tu kuwa na rundo zima la ikiwa na kusema, hmm, kama idadi hii ya kwanza ni 4, 282 00:10:10,460 --> 00:10:11,800 basi mimi kuruka njia yote hadi mwisho. 283 00:10:11,800 --> 00:10:14,180 Ooh, kama idadi hiyo ni kubwa mno, basi mimi hoja kiholela nyuma 284 00:10:14,180 --> 00:10:15,220 na kipengele cha pili. 285 00:10:15,220 --> 00:10:18,210 Utakuta kwamba ni kwenda kuwa mengi vigumu kurasimisha nini sisi wanadamu 286 00:10:18,210 --> 00:10:21,270 kuchukua kwa nafasi kama ya busara sana heuristics, lakini kompyuta ni tu 287 00:10:21,270 --> 00:10:23,260 kwenda kufanya nini kuwaambia yake ya kufanya. 288 00:10:23,260 --> 00:10:25,280 >> Sasa hii ina kuvutia sana athari. 289 00:10:25,280 --> 00:10:29,950 Graph hii ni aina ya maana ya aina ya overwhelm kuibua, lakini taarifa, ambapo 290 00:10:29,950 --> 00:10:32,230 ni line moja kwa moja katika graph hii? 291 00:10:32,230 --> 00:10:35,330 Ambapo ni graph linear kwamba sisi kuwaita n? 292 00:10:35,330 --> 00:10:37,580 Naam, ni aina ya kuelekea chini ya picha hii, haki? 293 00:10:37,580 --> 00:10:40,500 Hivyo wote tumefanya ni tumekuwa aina ya zoomed nje ya mhimili x-na 294 00:10:40,500 --> 00:10:44,780 y-mhimili kujaribu kupata hisia ya kile aina nyingine ya curves kuangalia kama. 295 00:10:44,780 --> 00:10:47,760 >> Na specifics ya hisabati maneno leo si jambo hivyo 296 00:10:47,760 --> 00:10:52,440 sana, lakini taarifa kwamba kuna mengi ya algorithms kwamba ni mbaya zaidi kuliko 297 00:10:52,440 --> 00:10:53,470 kitu ambacho ni linear. 298 00:10:53,470 --> 00:10:55,410 Hakika, n uliokatwakatwa inaonekana pretty mbaya. 299 00:10:55,410 --> 00:10:58,400 2 kwa n inaonekana pretty mbaya. n squared inaonekana pretty mbaya. 300 00:10:58,400 --> 00:11:01,630 Na tutaweza kuona nini baadhi ya wale wanaweza kuwa katika hali halisi ya leo. 301 00:11:01,630 --> 00:11:05,430 Na logi n haina kujisikia kama mbaya, lakini bora kuliko n ni logi msingi ya 2 ya n. 302 00:11:05,430 --> 00:11:08,080 Lakini unajua, ingekuwa hata kushangaza zaidi kama Jennifer, au kama sisi, 303 00:11:08,080 --> 00:11:12,910 kwamba wiki ya kwanza, alikuwa na kuja na kitu ambacho ni logi ya logi ya n. 304 00:11:12,910 --> 00:11:15,880 >> Hivyo kwa maneno mengine, kuna hii nzima mbalimbali ya ufumbuzi inawezekana 305 00:11:15,880 --> 00:11:18,570 matatizo, lakini hata hapa, ilani nini kinaendelea kutokea. 306 00:11:18,570 --> 00:11:22,910 Wakati mimi zoom nje, ambayo ya curves hawa ni kwenda kuthibitisha kuwa kabisa 307 00:11:22,910 --> 00:11:26,630 mbaya zaidi ya wale wa kwenye screen sasa? 308 00:11:26,630 --> 00:11:28,680 Hivyo n cubed inaonekana pretty mbaya kwa sasa. 309 00:11:28,680 --> 00:11:32,470 Lakini kama sisi zoom nje na kuona zaidi ya x na y-mhimili, ambaye ni kwenda 310 00:11:32,470 --> 00:11:34,550 kutawala hatimaye? 311 00:11:34,550 --> 00:11:37,120 Hivyo ni kweli zinageuka kuwa 2 hadi n, na unaweza takwimu hii nje tu na 312 00:11:37,120 --> 00:11:39,990 plugging katika baadhi inazidi kubwa namba, na utaona kwamba 2 kwa 313 00:11:39,990 --> 00:11:42,070 n, kwa kweli, anapata kubwa kwa kasi zaidi. 314 00:11:42,070 --> 00:11:45,530 Kama sisi kweli zoom nje, 2 kwa n algorithm kabisa sucks. 315 00:11:45,530 --> 00:11:48,170 I mean hii ni kwenda kuchukua kidogo kabisa ya muda kwa ajili ya 316 00:11:48,170 --> 00:11:49,460 kompyuta churn kupitia. 317 00:11:49,460 --> 00:11:52,500 >> Lakini utaona baada ya muda, hasa na baadaye tatizo seti na hata 318 00:11:52,500 --> 00:11:55,600 miradi ya mwisho, ni data yako kuweka anapata kubwa, wote haki? 319 00:11:55,600 --> 00:11:58,300 Hata katika toleo la kwanza la Facebook, kama idadi ya marafiki, na 320 00:11:58,300 --> 00:12:01,840 idadi ya watumiaji waliojiandikisha got kubwa, unaweza aina ya simu katika na 321 00:12:01,840 --> 00:12:05,530 kutekeleza kitu na tafuta linear, au kuchagua rahisi sana 322 00:12:05,530 --> 00:12:07,030 algorithm, kama tutaweza kuona leo. 323 00:12:07,030 --> 00:12:09,280 Una kuanza kufikiri vigumu na vigumu juu ya matatizo haya. 324 00:12:09,280 --> 00:12:12,070 Na aina ya maeneo matatizo kama Facebook, na Google, na Microsoft, 325 00:12:12,070 --> 00:12:16,350 na wengine kazi ya ni hasa hizi aina ya aina kubwa ya data ya maswali 326 00:12:16,350 --> 00:12:18,530 inazidi siku hizi. 327 00:12:18,530 --> 00:12:18,900 >> Wote haki. 328 00:12:18,900 --> 00:12:23,800 Hivyo mafanikio Jennifer ya pili kwa kuwa algorithm, kusema ukweli, yeye alifanya kushangaza 329 00:12:23,800 --> 00:12:26,110 vizuri mara ya kwanza, lakini hebu kuandika ni kama bahati hivyo kwamba sisi 330 00:12:26,110 --> 00:12:27,000 unaweza kufanya hatua hii. 331 00:12:27,000 --> 00:12:30,970 Katika kesi ya pili, yeye leveraged algorithm kwamba alirudia tena na 332 00:12:30,970 --> 00:12:34,670 tena, lakini yeye alichukua kwa nafasi baadhi ya dhana kwamba sisi kuruhusiwa 333 00:12:34,670 --> 00:12:39,370 yake, lakini yeye vibaya baadhi ya kina pili wakati huo yeye hakuwa na 334 00:12:39,370 --> 00:12:39,840 mara ya kwanza. 335 00:12:39,840 --> 00:12:41,800 Ambayo ilikuwa ni nini? 336 00:12:41,800 --> 00:12:43,050 >> Hiyo ilikuwa orodha Iliyopangwa. 337 00:12:43,050 --> 00:12:46,350 Hivyo kwa haraka kama orodha ilikuwa sorted, sisi kudai kwamba Jennifer alikuwa na uwezo wa kufanya 338 00:12:46,350 --> 00:12:47,480 kimsingi bora. 339 00:12:47,480 --> 00:12:51,450 7 milango, ndiyo, ni kwamba kuvutia, lakini tuseme sisi ni milioni 7 milango. 340 00:12:51,450 --> 00:12:54,080 Logi ya n ni dhahiri kwenda kufanya mengi, 341 00:12:54,080 --> 00:12:55,610 kasi zaidi katika muda mrefu. 342 00:12:55,610 --> 00:12:58,880 Lakini yeye alikuwa na kuwa na milango yamepangwa kwa ajili yake. 343 00:12:58,880 --> 00:13:02,320 Sasa, mimi alichukua uhuru wa kufanya hivyo mapema kwenye screen ya kompyuta 344 00:13:02,320 --> 00:13:05,160 hapa, lakini tuseme kwamba Jennifer ilibidi kufanya hivyo mwenyewe? 345 00:13:05,160 --> 00:13:10,120 Tuseme kwamba milango katika swali kuwakilishwa data katika database, au 346 00:13:10,120 --> 00:13:14,260 marafiki kusajiliwa kwa Facebook, au kurasa za mtandao yoyote kwenye mtandao kwamba 347 00:13:14,260 --> 00:13:16,880 tovuti mbalimbali ili haja index au tafuta juu. 348 00:13:16,880 --> 00:13:20,940 >> Tuseme kwamba wewe tu alikuwa takwimu ghafi kuweka na ilikuwa kushoto na wewe, au kwa 349 00:13:20,940 --> 00:13:23,010 Jennifer kufanya kwamba kuchagua? 350 00:13:23,010 --> 00:13:26,950 Kwamba, badala yake, inahitaji kuwa sisi kujibu swali, vizuri, ni kiasi gani wakati 351 00:13:26,950 --> 00:13:31,080 ingekuwa kuchukuliwa Jennifer, au hata mimi, kutatua namba hizo mapema ili 352 00:13:31,080 --> 00:13:32,680 kwamba anaweza kuchukua faida ya kwamba? 353 00:13:32,680 --> 00:13:32,880 Haki? 354 00:13:32,880 --> 00:13:36,620 Kwa sababu maana halisi, bila shaka, ni kama inachukua mimi wakati kabisa ya kutatua 355 00:13:36,620 --> 00:13:40,800 namba, ambaye heck anayejali kwamba wewe unaweza kupata idadi kama 50 kwa haraka sana, 356 00:13:40,800 --> 00:13:44,850 kama katika kesi ya Jennifer, kama sisi zaidi ya kuzidiwa kiasi cha muda wa taarifa 357 00:13:44,850 --> 00:13:46,920 ilichukua na kuchagua mambo mapema? 358 00:13:46,920 --> 00:13:49,320 >> Basi hebu angalia kama hatuwezi kuchora picha hapa. 359 00:13:49,320 --> 00:13:51,370 Nina rundo zima zaidi mkazo mipira, kama ambayo husaidia 360 00:13:51,370 --> 00:13:52,270 kuvunja barafu hapa. 361 00:13:52,270 --> 00:13:55,690 Na kama wewe bila akili, sisi haja saba kujitolea - 362 00:13:55,690 --> 00:13:57,060 juu, OK. 363 00:13:57,060 --> 00:13:57,240 Wow. 364 00:13:57,240 --> 00:13:59,250 Hivyo hatuwezi kuwa na kutumia juu ya taa dawati, inaonekana. 365 00:13:59,250 --> 00:13:59,690 Wote haki. 366 00:13:59,690 --> 00:14:01,530 Basi vipi kuhusu wewe mbili mbele. 367 00:14:01,530 --> 00:14:04,160 Vipi kuhusu wewe guys wawili katika nyuma. 368 00:14:04,160 --> 00:14:04,870 Hivyo kwamba ni nne. 369 00:14:04,870 --> 00:14:09,890 Vipi kuhusu wewe mbele tano, sita na saba. 370 00:14:09,890 --> 00:14:10,320 Haki huko. 371 00:14:10,320 --> 00:14:13,260 Rafiki yako ni akizungumzia wewe nje, ili kupata tuzo. 372 00:14:13,260 --> 00:14:13,700 >> Wote haki. 373 00:14:13,700 --> 00:14:14,410 Kuja juu juu. 374 00:14:14,410 --> 00:14:17,120 Na kwa nini sio sisi kuwa na wewe guys kuja juu zaidi ya hapa. 375 00:14:17,120 --> 00:14:18,960 Mimi naenda kukupa kila aina ya simu. 376 00:14:18,960 --> 00:14:22,150 Na kwenda mbele na kupanga wenyewe identically kwa nini 377 00:14:22,150 --> 00:14:25,180 taswira kwenye screen. 378 00:14:25,180 --> 00:14:26,530 >> [INTERPOSING SAUTI] 379 00:14:26,530 --> 00:14:28,160 >> DAVID J. Malan: OOP, pole. 380 00:14:28,160 --> 00:14:30,210 Mdudu. 381 00:14:30,210 --> 00:14:32,180 Wote haki. 382 00:14:32,180 --> 00:14:32,750 Vizuri, hapa sisi kwenda. 383 00:14:32,750 --> 00:14:34,180 Namba tano. 384 00:14:34,180 --> 00:14:35,136 Idadi sita. 385 00:14:35,136 --> 00:14:37,770 Moja, mbili, tatu, nne, tano, sita, saba. 386 00:14:37,770 --> 00:14:39,410 Oh, hii ni Awkward. 387 00:14:39,410 --> 00:14:41,210 >> SPIKA 2: Mimi itabidi kupata -. 388 00:14:41,210 --> 00:14:41,900 >> DAVID J. Malan: Good mpango huo. 389 00:14:41,900 --> 00:14:43,130 Wote haki. 390 00:14:43,130 --> 00:14:44,611 Asante kwa kushiriki. 391 00:14:44,611 --> 00:14:47,200 >> [Makofi] 392 00:14:47,200 --> 00:14:48,580 >> OK. 393 00:14:48,580 --> 00:14:48,860 Wote haki. 394 00:14:48,860 --> 00:14:51,970 Hivyo tuna nne, mbili, sita, moja, tatu, saba, watano. 395 00:14:51,970 --> 00:14:56,010 Tutimilizie hivyo tuna kujitolea saba hapa ambao ni sawa katika upana na 396 00:14:56,010 --> 00:14:57,430 safu kwamba sisi ni kucheza na mapema. 397 00:14:57,430 --> 00:14:59,470 Na mimi alichagua saba kwa sababu kwamba itakuwa tu 398 00:14:59,470 --> 00:15:00,840 urahisi katika kidogo. 399 00:15:00,840 --> 00:15:04,400 Na mimi nina kwenda kupendekeza kwanza kwamba sisi kutatua kujitolea haya saba. 400 00:15:04,400 --> 00:15:06,786 Kama Ningependa, kwanza, kusema hello ingawa. 401 00:15:06,786 --> 00:15:08,970 Tangu hii ni kwenda kuwa Awkward dakika kadhaa. 402 00:15:08,970 --> 00:15:10,370 Kuanzisha wenyewe. 403 00:15:10,370 --> 00:15:10,980 >> GRACE: Hi, mimi nina Grace. 404 00:15:10,980 --> 00:15:14,190 Mimi nina sophomore katika LEVERETT House. 405 00:15:14,190 --> 00:15:14,620 >> BRANSON: Hi. 406 00:15:14,620 --> 00:15:15,620 Mimi nina Branson. 407 00:15:15,620 --> 00:15:16,920 Mimi nina Freshman katika weld. 408 00:15:16,920 --> 00:15:19,755 409 00:15:19,755 --> 00:15:20,230 >> GABE: Hi. 410 00:15:20,230 --> 00:15:21,040 Mimi nina Gabe. 411 00:15:21,040 --> 00:15:22,300 Mimi nina junior katika Cabot. 412 00:15:22,300 --> 00:15:24,826 413 00:15:24,826 --> 00:15:25,980 >> NEIL: Mimi nina Neil. 414 00:15:25,980 --> 00:15:29,090 Mimi nina Freshman katika Matthews. 415 00:15:29,090 --> 00:15:29,550 >> JASON: Mimi nina Jason. 416 00:15:29,550 --> 00:15:32,816 Mimi nina Freshman katika GREENOUGH. 417 00:15:32,816 --> 00:15:33,700 >> MIKE: Mimi nina Mike. 418 00:15:33,700 --> 00:15:37,360 Mimi nina Freshman katika Grays. 419 00:15:37,360 --> 00:15:37,990 >> JESS: Mimi nina Jess. 420 00:15:37,990 --> 00:15:40,313 Mimi nina sophomore katika LEVERETT. 421 00:15:40,313 --> 00:15:41,300 >> DAVID J. Malan: Mufti. 422 00:15:41,300 --> 00:15:41,850 Wote haki. 423 00:15:41,850 --> 00:15:44,190 Naam, asante kwa yote ya yetu ya kujitolea hapa hivi sasa. 424 00:15:44,190 --> 00:15:47,110 Na changamoto katika mkono sasa ni kwenda kuwa na aina ya guys haya, lakini basi 425 00:15:47,110 --> 00:15:50,250 tunakwenda na kufikiri kidogo sana kuhusu jinsi ufanisi sisi kweli 426 00:15:50,250 --> 00:15:51,110 namna yao. 427 00:15:51,110 --> 00:15:52,580 Basi hebu kwanza jaribu hii. 428 00:15:52,580 --> 00:15:55,970 Wewe guys unaweza kuona idadi ya kila mmoja tu kwa kuweka kuzunguka pembe. 429 00:15:55,970 --> 00:15:59,380 Kwenda mbele na kuchukua sekunde chache, na aina kujiona kutoka ndogo ya 430 00:15:59,380 --> 00:16:01,240 kushoto na ukubwa juu ya haki. 431 00:16:01,240 --> 00:16:02,490 Kwenda. 432 00:16:02,490 --> 00:16:07,010 433 00:16:07,010 --> 00:16:07,530 >> OK. 434 00:16:07,530 --> 00:16:08,030 Nzuri. 435 00:16:08,030 --> 00:16:09,370 Kwamba alikuwa kweli darn haraka. 436 00:16:09,370 --> 00:16:14,040 Sasa mtu hapa, nini ilikuwa algorithm kwamba hawa guys kutumika? 437 00:16:14,040 --> 00:16:14,900 >> SPIKA 1: Haiko na wakubwa. 438 00:16:14,900 --> 00:16:15,000 >> DAVID J. Malan: OK. 439 00:16:15,000 --> 00:16:18,070 Mdogo hata mkubwa ni kweli aina ya lengo, lakini mimi nina uhakika kwamba 440 00:16:18,070 --> 00:16:18,890 kweli algorithm. 441 00:16:18,890 --> 00:16:21,810 Mdogo hadi mkubwa haina kuwaambia mimi hatua kwa hatua nini cha kufanya. 442 00:16:21,810 --> 00:16:22,833 Yeah? 443 00:16:22,833 --> 00:16:24,083 >> SPIKA 1: [inaudible] 444 00:16:24,083 --> 00:16:26,010 445 00:16:26,010 --> 00:16:26,280 >> DAVID J. Malan: OK. 446 00:16:26,280 --> 00:16:28,920 Hivyo kama unaweza kuona mtu ndogo kuliko simu yako, basi hoja ya 447 00:16:28,920 --> 00:16:29,680 haki yao. 448 00:16:29,680 --> 00:16:32,800 Hivyo kwamba ni sasa kupata zaidi expressive, zaidi kama algorithm, kwa sababu wewe 449 00:16:32,800 --> 00:16:35,410 unaweza kusema, kama hii, basi hiyo. 450 00:16:35,410 --> 00:16:37,050 Hivyo tuna baadhi ya aina ya masharti ya kujenga. 451 00:16:37,050 --> 00:16:39,700 Na haya guys walionekana kufanya kwamba wachache mara, kwa sababu baadhi yenu wakiongozwa kidogo 452 00:16:39,700 --> 00:16:40,420 wa umbali. 453 00:16:40,420 --> 00:16:43,410 Hivyo kulikuwa na labda baadhi ya aina ya looping kinachoendelea katika akili zao. 454 00:16:43,410 --> 00:16:44,610 >> Lakini hebu jaribu kurasimisha kwamba. 455 00:16:44,610 --> 00:16:47,540 Kama wewe guys inaweza upya nyuma kwa mpangilio huu. 456 00:16:47,540 --> 00:16:50,650 Hebu angalia kama hatuwezi kurasimisha hii kidogo, na kisha kuuliza swali, tu 457 00:16:50,650 --> 00:16:51,580 jinsi ya ufanisi ni hii? 458 00:16:51,580 --> 00:16:54,220 Bila shaka, wakati sisi kufanya hivyo polepole zaidi, ni kwenda kujisikia kama nzuri ya 459 00:16:54,220 --> 00:16:57,210 algorithm, lakini hebu angalia kama tunaweza kuweka vidole wetu juu ya hatua sahihi. 460 00:16:57,210 --> 00:16:58,670 >> Hivyo wewe guys wawili ni nne na mbili. 461 00:16:58,670 --> 00:17:01,020 Au wewe sahihi au sio sahihi ili? 462 00:17:01,020 --> 00:17:01,900 Ni wazi sahihi. 463 00:17:01,900 --> 00:17:02,710 Hivyo sisi walibadilishana. 464 00:17:02,710 --> 00:17:05,170 Sasa mimi nina kwenda kwa hoja kando hapa na kusema, watu wanne hadi sita. 465 00:17:05,170 --> 00:17:06,240 Je, wewe ni sahihi au si sahihi? 466 00:17:06,240 --> 00:17:06,599 >> GABE: Sahihi. 467 00:17:06,599 --> 00:17:07,180 >> DAVID J. Malan: Sahihi. 468 00:17:07,180 --> 00:17:08,300 Sita na moja? 469 00:17:08,300 --> 00:17:08,609 Nope. 470 00:17:08,609 --> 00:17:09,630 Wabadilishane. 471 00:17:09,630 --> 00:17:10,490 Hivyo kwamba ni wawili swaps. 472 00:17:10,490 --> 00:17:11,710 Sita na tatu? 473 00:17:11,710 --> 00:17:11,980 Nope. 474 00:17:11,980 --> 00:17:13,000 Wabadilishane. 475 00:17:13,000 --> 00:17:13,930 Sita na saba? 476 00:17:13,930 --> 00:17:14,630 Inaonekana nzuri. 477 00:17:14,630 --> 00:17:15,396 Saba na tano? 478 00:17:15,396 --> 00:17:16,150 >> JESS: [inaudible] 479 00:17:16,150 --> 00:17:17,089 >> DAVID J. Malan: OK, wabadilishane. 480 00:17:17,089 --> 00:17:19,770 Na kuchambua. 481 00:17:19,770 --> 00:17:19,980 Wote haki. 482 00:17:19,980 --> 00:17:21,440 Hivyo ni wazi, sawa? 483 00:17:21,440 --> 00:17:22,470 Hivyo kuna ilikuwa zaidi kinachoendelea. 484 00:17:22,470 --> 00:17:24,920 Lakini, kwa hakika, hawa guys, hata tu kisilika. 485 00:17:24,920 --> 00:17:25,450 naendelea kusonga mbele. 486 00:17:25,450 --> 00:17:27,710 Hawakuwa kuacha tu, mara wao kusahihishwa tatizo moja. 487 00:17:27,710 --> 00:17:27,839 Hivyo. 488 00:17:27,839 --> 00:17:29,390 Hakika, mimi naenda kuwa kufanya kitu kimoja. 489 00:17:29,390 --> 00:17:32,720 Mimi naenda kuwa na aina ya nyuma rewind mwanzo wa tatizo hili, 490 00:17:32,720 --> 00:17:35,630 au mwanzo wa safu hii ya watu, hebu kuanza kuwaita. 491 00:17:35,630 --> 00:17:38,366 >> Na sasa nini lazima yangu algorithm juu ya kupita ya pili kuwa? 492 00:17:38,366 --> 00:17:39,220 >> SPIKA 1: Same kitu. 493 00:17:39,220 --> 00:17:39,940 >> DAVID J. Malan: Same kitu. 494 00:17:39,940 --> 00:17:41,460 Na hii, mimi nina kuanza kama, sawa? 495 00:17:41,460 --> 00:17:44,720 Haraka kama unaweza kupata mwenyewe kufanya kitu kimoja tena na tena, kwamba ni 496 00:17:44,720 --> 00:17:47,890 kuwa zaidi kama algorithm, na chini ya binadamu Instinct. 497 00:17:47,890 --> 00:17:48,680 >> Hivyo sasa, hapa sisi kwenda tena. 498 00:17:48,680 --> 00:17:49,870 Mbili na nne? 499 00:17:49,870 --> 00:17:50,220 No 500 00:17:50,220 --> 00:17:51,050 Nne na moja? 501 00:17:51,050 --> 00:17:53,380 Ah, hakika kuna baadhi ya kazi bado ya kufanyika. 502 00:17:53,380 --> 00:17:53,620 Kwa na tatu? 503 00:17:53,620 --> 00:17:54,572 Nzuri. 504 00:17:54,572 --> 00:17:56,000 Nne na sita? 505 00:17:56,000 --> 00:17:58,380 Sita na tano? 506 00:17:58,380 --> 00:17:59,470 Sita na saba? 507 00:17:59,470 --> 00:18:00,970 OK, sasa, kufanyika. 508 00:18:00,970 --> 00:18:01,550 OK, hakuna. 509 00:18:01,550 --> 00:18:02,710 Mimi kwenda nyuma. 510 00:18:02,710 --> 00:18:05,130 >> Hivyo sasa, tena, sisi ni kufanya hii kidogo zaidi kwa makusudi. 511 00:18:05,130 --> 00:18:08,700 Na sasa, kuna moja tu ya ubongo utekelezaji hii algorithm. 512 00:18:08,700 --> 00:18:10,290 Moja CPU, kama wewe. 513 00:18:10,290 --> 00:18:13,090 Na kusema ukweli, kwamba ni rasilimali tu tunakwenda kupata. 514 00:18:13,090 --> 00:18:16,280 Na mara moja hatuwezi kwenda nyuma ya keyboard na kuwa na kitu kama C saa wetu 515 00:18:16,280 --> 00:18:19,600 ovyo, tuko tu kuandika mpango kwamba wanaweza kufanya jambo moja kwa wakati. 516 00:18:19,600 --> 00:18:22,900 Wakati ambapo, haya guys wakati iliyopita, sisi leveraged brainpower yao ya pamoja 517 00:18:22,900 --> 00:18:24,180 kama wewe guys alivyofanya katika sifuri wiki. 518 00:18:24,180 --> 00:18:24,980 Basi hebu kuendelea kufanya hii. 519 00:18:24,980 --> 00:18:26,260 >> Mbili na moja. 520 00:18:26,260 --> 00:18:26,945 Mbili na tatu. 521 00:18:26,945 --> 00:18:27,460 Tatu na nne. 522 00:18:27,460 --> 00:18:28,310 Nne na tano. 523 00:18:28,310 --> 00:18:28,620 Tano na sita. 524 00:18:28,620 --> 00:18:30,510 Sita na saba. 525 00:18:30,510 --> 00:18:31,880 Kufanyika? 526 00:18:31,880 --> 00:18:34,560 Hivyo mimi, lakini napenda kucheza shetani mtetezi. 527 00:18:34,560 --> 00:18:37,950 Je, mimi, aina ya kompyuta ambao tu alifanya kupita hii safu ya 528 00:18:37,950 --> 00:18:40,225 watu, kujua kwamba mimi nina kufanyika? 529 00:18:40,225 --> 00:18:40,670 >> SPIKA 1: Hapana 530 00:18:40,670 --> 00:18:41,050 >> DAVID J. Malan: Basi kwa nini? 531 00:18:41,050 --> 00:18:46,900 Gani mimi kufanya ili kuhitimisha uamuzi kwamba mimi kufanyika? 532 00:18:46,900 --> 00:18:48,230 Pengine moja zaidi kupita. 533 00:18:48,230 --> 00:18:48,430 Haki? 534 00:18:48,430 --> 00:18:51,760 Kwa sababu najua wote kutoka kwamba uliopita kupita ni kwamba mimi kusahihishwa makosa. 535 00:18:51,760 --> 00:18:53,920 Na kwamba njia, labda kuna bado makosa mwingine 536 00:18:53,920 --> 00:18:54,840 kwamba mimi haja ya kusahihisha. 537 00:18:54,840 --> 00:18:58,680 Hivyo naweza tu kuwa na uhakika na rewinding, na kisha kuangalia, na moja hadi mbili, mbili 538 00:18:58,680 --> 00:19:00,940 tatu, tatu na nne, nne na tano, tano na sita, sita na saba. 539 00:19:00,940 --> 00:19:02,510 Sawa, sasa mimi hakuna kazi. 540 00:19:02,510 --> 00:19:05,990 >> Mimi tunaweza kukumbuka kwamba mimi hakuna kazi na kitu kama variable, 541 00:19:05,990 --> 00:19:06,975 kama int. 542 00:19:06,975 --> 00:19:12,490 Kuiita swaps, na kama swaps ni 0 mara moja mimi kupata hapa, na ilianza saa 0, kisha 543 00:19:12,490 --> 00:19:15,520 Napenda tu kuwa kijinga na kuendelea na kurudi, kuangalia tena, na 544 00:19:15,520 --> 00:19:16,450 tena, na tena, haki? 545 00:19:16,450 --> 00:19:18,450 Kwa sababu wewe kukwama katika baadhi ya aina ya kitanzi usio. 546 00:19:18,450 --> 00:19:21,250 Hivyo kwa haraka kama kuna 0 swaps, tunaweza kudai kwamba hii 547 00:19:21,250 --> 00:19:23,810 algorithm ni kweli kabisa. 548 00:19:23,810 --> 00:19:25,400 >> Sasa, hebu kuweka jina juu ya hili. 549 00:19:25,400 --> 00:19:28,930 algorithm kwamba napendekeza sisi tu kutekelezwa ni kitu kinachoitwa Bubble 550 00:19:28,930 --> 00:19:32,800 aina, unaojulikana kama vile kwa maana ya kwamba idadi ambayo ni kubwa aina ya 551 00:19:32,800 --> 00:19:37,990 Bubble njia yao hadi juu, au hadi hadi mwisho wa safu ya idadi. 552 00:19:37,990 --> 00:19:40,270 Lakini jinsi ufanisi alikuwa algorithm hii? 553 00:19:40,270 --> 00:19:44,600 Jinsi gani mimi hatua nyingi kimwili na kuchukua, kwa mfano, kwa aina hizi 554 00:19:44,600 --> 00:19:45,850 saba binadamu? 555 00:19:45,850 --> 00:19:48,560 556 00:19:48,560 --> 00:19:49,550 >> Nne na tano? 557 00:19:49,550 --> 00:19:51,420 OK, pia wengi ni hatimaye kwenda kuwa jibu. 558 00:19:51,420 --> 00:19:54,960 Lakini hata hivyo, idadi maalum si hivyo kuvutia. 559 00:19:54,960 --> 00:19:56,670 Hebu generalize kama n. 560 00:19:56,670 --> 00:20:00,520 Hivyo kama mimi alikuwa n watu hapa juu, na wao walikuwa, aina ya, ili random katika 561 00:20:00,520 --> 00:20:02,180 mwanzo, ili awali. 562 00:20:02,180 --> 00:20:04,910 Vizuri, jinsi gani hatua nyingi nina kuchukua juu ya kupita ya kwanza? 563 00:20:04,910 --> 00:20:09,810 Ilikuwa ni moja, mbili, tatu, nne, tano, sita, na wao ni watu saba, hivyo 564 00:20:09,810 --> 00:20:13,670 hiyo ni saba, sita -, hivyo kwamba ni n bala moja hatua mara ya kwanza. 565 00:20:13,670 --> 00:20:16,280 >> Sasa, jinsi hatua nyingi gani mimi kuwa kuchukua wakati mimi rewound? 566 00:20:16,280 --> 00:20:19,310 Naam, sisi inaweza kweli mara mbili kwamba kama sisi kweli alitaka, lakini kwa sasa, mimi nina 567 00:20:19,310 --> 00:20:22,300 kwenda tu kusema, haki ya wote, mwingine n bala 1. 568 00:20:22,300 --> 00:20:25,240 Hivyo bala n 1 ni kwenda kupata annoying kuweka wimbo wa, hivyo hebu 569 00:20:25,240 --> 00:20:26,400 tu pande zote juu kidogo. 570 00:20:26,400 --> 00:20:27,770 Hivyo 2n hatua. 571 00:20:27,770 --> 00:20:29,310 Hivyo hatua 14, kutoa au kuchukua. 572 00:20:29,310 --> 00:20:31,930 >> Mara ngapi mimi kuchukua hatua wakati ujao? 573 00:20:31,930 --> 00:20:33,740 Naam, ni 3N. 574 00:20:33,740 --> 00:20:34,510 kweli. 575 00:20:34,510 --> 00:20:37,920 Na sasa, katika hali mbaya zaidi, kwa mfano, mara ngapi nimetaka kuwa 576 00:20:37,920 --> 00:20:41,730 gone na kurudi, na kurudi, utekelezaji hii algorithm, swapping 577 00:20:41,730 --> 00:20:44,620 watu juu ya kupita kila aina, takribani? 578 00:20:44,620 --> 00:20:47,720 579 00:20:47,720 --> 00:20:50,010 Ni kweli n mraba, sawa? 580 00:20:50,010 --> 00:20:53,000 >> Kwa sababu katika hali mbaya zaidi, unaweza aina ya kufikiri juu ya hili intuitively, 581 00:20:53,000 --> 00:20:54,800 hata ingawa inaweza kuchukua kidogo muda kidogo kuzama in 582 00:20:54,800 --> 00:20:57,590 Katika hali mbaya zaidi, gani hizi watu saba kuwa inaonekana kama, katika 583 00:20:57,590 --> 00:21:00,230 suala la mpangilio ya idadi yao? 584 00:21:00,230 --> 00:21:01,460 Kabisa nyuma, haki? 585 00:21:01,460 --> 00:21:02,815 Na tu kuiga kwamba, nini ilikuwa jina yako tena? 586 00:21:02,815 --> 00:21:03,360 >> MIKE: Mike. 587 00:21:03,360 --> 00:21:03,640 >> DAVID J. Malan: Mike? 588 00:21:03,640 --> 00:21:08,100 OK, Mike, unaweza tu kujiunga na mimi juu ya hapa kwa ajili tu ya pili moja? 589 00:21:08,100 --> 00:21:08,880 Kweli, hakuna. 590 00:21:08,880 --> 00:21:10,150 Pole Mike, rewind hebu. 591 00:21:10,150 --> 00:21:10,910 Nini jina lako tena? 592 00:21:10,910 --> 00:21:11,180 >> NEIL: Neil. 593 00:21:11,180 --> 00:21:11,640 >> DAVID J. Malan: Neil. 594 00:21:11,640 --> 00:21:13,750 OK, Neil, wewe kuja na mimi, kama huna akili. 595 00:21:13,750 --> 00:21:17,150 Hivyo nina kwenda kwa kupendekeza, tu kwa ajili ya unyenyekevu, kwamba Neil sasa ni katika wake 596 00:21:17,150 --> 00:21:18,510 mbaya inawezekana kesi. 597 00:21:18,510 --> 00:21:20,720 Lakini wanakumbuka jinsi mimi kutekelezwa yangu algorithm. 598 00:21:20,720 --> 00:21:24,530 Mimi kulinganisha, kulinganisha, kulinganisha, kulinganisha, kulinganisha, oh. 599 00:21:24,530 --> 00:21:26,640 Sasa haya guys ni nje ya utaratibu, hivyo mimi kurekebisha. 600 00:21:26,640 --> 00:21:27,980 Hivyo wewe guys wabadilishane. 601 00:21:27,980 --> 00:21:31,630 Lakini fikiria sasa, jinsi mbali zaidi haina Neil na kwenda? 602 00:21:31,630 --> 00:21:32,690 Ni takribani n. 603 00:21:32,690 --> 00:21:33,570 Unajua, siyo kweli n. 604 00:21:33,570 --> 00:21:36,040 Ni kama, n bala 1, lakini nina kupata annoyed kuweka wimbo wa kidogo 605 00:21:36,040 --> 00:21:37,550 simu, hivyo hebu tu kuiita n. 606 00:21:37,550 --> 00:21:42,860 >> Hivyo kama Neil hatua hatua moja maximally kila wakati, na kwa hoja Neil hatua moja, 607 00:21:42,860 --> 00:21:46,580 Nina kufanya hii kupita kweli tedious na kurudi, hii ni takribani 608 00:21:46,580 --> 00:21:52,080 kufanya hivyo, n hatua, jumla ya mara n, kwa sababu ni kwenda kuchukua yangu 609 00:21:52,080 --> 00:21:55,820 kwamba hatua nyingi kupata Neil kila njia ambapo yeye ni mwanachama. 610 00:21:55,820 --> 00:21:58,620 Achilia kila mtu mwingine kama wewe guys wote walikuwa mis-kuamuru pia. 611 00:21:58,620 --> 00:22:01,100 >> Basi hebu piga Bubble aina n squared. 612 00:22:01,100 --> 00:22:04,860 wakati mbio ya algorithm hii, utendaji wa algorithm hii, 613 00:22:04,860 --> 00:22:07,120 ufanisi wa algorithm hii, sisi ndio tu kuelezea zaidi 614 00:22:07,120 --> 00:22:08,800 ujumla kama n squared. 615 00:22:08,800 --> 00:22:11,650 Ambayo ni nzuri, kwa sababu mimi naweza kufanya huo mfano na watu nane, tisa 616 00:22:11,650 --> 00:22:15,450 watu, watu milioni, na kwamba Jibu ni si kwenda na mabadiliko. 617 00:22:15,450 --> 00:22:18,870 >> Hivyo kama wewe guys bila akili, hebu upya wewe ambapo wewe kuanza. 618 00:22:18,870 --> 00:22:22,510 Na hebu jaribu njia nyingine mbili na kuona kama hatuwezi kufanya kimsingi 619 00:22:22,510 --> 00:22:23,820 bora zaidi kuliko haya. 620 00:22:23,820 --> 00:22:27,130 Hivyo wakati huu, mimi nina kwenda kupendekeza aina ya algorithm tofauti. 621 00:22:27,130 --> 00:22:29,950 Hiyo ilikuwa ni wajanja sana wa kwetu mara ya mwisho, na nyie walikuwa na haki ya kuwa na 622 00:22:29,950 --> 00:22:32,470 haki ya silika ya aina tu ya swapping pairwise. 623 00:22:32,470 --> 00:22:36,500 Lakini kama kweli alitaka mbinu hii tu, na lengo langu ni hoja 624 00:22:36,500 --> 00:22:39,800 wote wa idadi kidogo njia hii, na kushinikiza wote wa idadi kubwa kwamba 625 00:22:39,800 --> 00:22:43,030 njia, kwa nini sio mimi tu kufanya hivyo katika wengi wasiojua njia ya kutokea na kuona kama mimi 626 00:22:43,030 --> 00:22:45,730 wanaweza kufanya vizuri zaidi kuliko kile haki tata algorithm? 627 00:22:45,730 --> 00:22:46,620 >> Basi hebu angalia. 628 00:22:46,620 --> 00:22:48,940 Nne ni idadi pretty ndogo, hivyo mimi nina ataondoka wewe huko sasa. 629 00:22:48,940 --> 00:22:50,610 Ooh, namba mbili ni bora zaidi. 630 00:22:50,610 --> 00:22:52,230 Hivyo unaweza tu hatua mbele kwa muda? 631 00:22:52,230 --> 00:22:55,670 Hii sasa ni kuhesabiwa yangu ndogo mgombea, na mimi nina kwenda kukumbuka 632 00:22:55,670 --> 00:22:57,000 kwamba pamoja na, kama, kutofautiana. 633 00:22:57,000 --> 00:22:57,930 Lakini mimi nina kwenda kuendelea kuangalia. 634 00:22:57,930 --> 00:22:59,890 Je, kuna mtu ambaye idadi ni ndogo? 635 00:22:59,890 --> 00:23:00,460 Sita, hakuna. 636 00:23:00,460 --> 00:23:01,390 Oh, kuna Neil tena. 637 00:23:01,390 --> 00:23:04,050 >> Hivyo nina kwenda kushinikiza wewe nyuma aina ya kidhana. 638 00:23:04,050 --> 00:23:05,120 Neil atakuja mbele. 639 00:23:05,120 --> 00:23:08,440 Na sasa, variable kwamba mimi nina kutumia kwa kuweka wimbo wa nani ana ndogo 640 00:23:08,440 --> 00:23:11,390 simu ni updated na vyenye Neil ya mahali. 641 00:23:11,390 --> 00:23:12,110 Vizuri, hebu angalia. 642 00:23:12,110 --> 00:23:13,960 Tatu, saba, watano. 643 00:23:13,960 --> 00:23:15,590 OK, najua Neil ilikuwa ndogo. 644 00:23:15,590 --> 00:23:18,110 Nini jambo rahisi kwa mimi kufanya sasa? 645 00:23:18,110 --> 00:23:21,410 Mimi si kwenda kupoteza muda wangu na tu bubbling Neil moja doa wa kushoto. 646 00:23:21,410 --> 00:23:25,350 Kwa nini si mimi tu ya kuweka Neil ambapo yeye mali, ambayo ni mwendo wa wapi? 647 00:23:25,350 --> 00:23:26,160 >> Njia yote mwanzoni. 648 00:23:26,160 --> 00:23:27,720 Hivyo Neil, kuja na mimi. 649 00:23:27,720 --> 00:23:28,910 Na nini ilikuwa jina yako tena? 650 00:23:28,910 --> 00:23:29,310 >> GRACE: Grace. 651 00:23:29,310 --> 00:23:29,710 >> DAVID J. Malan: Grace. 652 00:23:29,710 --> 00:23:29,920 OK. 653 00:23:29,920 --> 00:23:32,490 Hivyo neema, kwa bahati mbaya, wewe ni aina ya njia. 654 00:23:32,490 --> 00:23:34,290 Hivyo ni jinsi gani sisi kutatua tatizo hili? 655 00:23:34,290 --> 00:23:34,490 Haki? 656 00:23:34,490 --> 00:23:37,500 Kama hii ni safu, kuna saba tu maeneo. 657 00:23:37,500 --> 00:23:40,830 Kumbuka kwamba, pamoja na Rob, kuongelea kutangaza milele, na sisi tu alikuwa 658 00:23:40,830 --> 00:23:41,740 finite idadi ya miaka? 659 00:23:41,740 --> 00:23:42,535 Same wazo hapa. 660 00:23:42,535 --> 00:23:44,300 Sisi tu idadi finite ya ints. 661 00:23:44,300 --> 00:23:47,590 Neema ni aina ya katika yetu njia, hivyo ni jinsi gani sisi kurekebisha? 662 00:23:47,590 --> 00:23:49,555 >> njia rahisi ni kama, Neema, pole. 663 00:23:49,555 --> 00:23:51,870 Wewe ni kwenda na kwenda juu huko ili tuweze kufanya chumba. 664 00:23:51,870 --> 00:23:55,290 Sasa, kama unafikiri juu ya hii, labda sisi tu alifanya tatizo mbaya. 665 00:23:55,290 --> 00:23:58,510 Na labda sisi alifanya, kwa sababu nini kama Neema walikuwa katika mahali sahihi? 666 00:23:58,510 --> 00:24:01,730 Lakini tunajua yeye si, kwa sababu vinginevyo, yeye ingekuwa 667 00:24:01,730 --> 00:24:03,980 wamesimama mbele badala ya Neil kwa wakati huu, haki? 668 00:24:03,980 --> 00:24:05,550 Sisi tayari checked simu yake ya nje. 669 00:24:05,550 --> 00:24:05,770 >> Wote haki. 670 00:24:05,770 --> 00:24:09,110 Hivyo sasa, Neil ni katika nafasi ya haki, na Naweza kufanya optimization kidogo. 671 00:24:09,110 --> 00:24:11,740 Kwa dakika ya pili, mimi nina kwenda kupuuza Neil wote kwa pamoja, hivyo kama si 672 00:24:11,740 --> 00:24:15,280 kupoteza muda wake, au kwa ajali wabadilishane naye mahali sahihi. 673 00:24:15,280 --> 00:24:17,805 Hivyo kwa sasa, jinsi gani mimi kupata ijayo kipengele kwamba ni madogo? 674 00:24:17,805 --> 00:24:18,480 Mbili. 675 00:24:18,480 --> 00:24:20,225 Hii ni idadi nzuri, kama unataka hatua mbele na 676 00:24:20,225 --> 00:24:21,100 Mimi itabidi kumbuka wewe. 677 00:24:21,100 --> 00:24:21,980 Sita, hakuna nzuri. 678 00:24:21,980 --> 00:24:24,820 Nne, tatu, saba, tano, si njema. 679 00:24:24,820 --> 00:24:26,800 Hivyo basi mimi hoja wewe nafasi yako ya haki. 680 00:24:26,800 --> 00:24:28,470 Na sisi tu got bahati wakati huu. 681 00:24:28,470 --> 00:24:31,350 >> Sasa, mimi nina kwenda kupuuza haya guys wawili, na sasa kufanya moja zaidi 682 00:24:31,350 --> 00:24:32,260 kupita kwa njia hii. 683 00:24:32,260 --> 00:24:33,490 Sita, kwamba idadi pretty ndogo. 684 00:24:33,490 --> 00:24:34,300 Kuja juu ya mbele. 685 00:24:34,300 --> 00:24:35,220 Oh, sorry. 686 00:24:35,220 --> 00:24:37,640 Idadi ya neema ni bora zaidi, hivyo hatua ya juu mbele. 687 00:24:37,640 --> 00:24:38,260 Nne. 688 00:24:38,260 --> 00:24:39,120 Samahani, Grace. 689 00:24:39,120 --> 00:24:39,950 Kurudi nyuma tena. 690 00:24:39,950 --> 00:24:41,550 Namba tatu ni bora. 691 00:24:41,550 --> 00:24:42,290 Saba. 692 00:24:42,290 --> 00:24:42,720 Tano. 693 00:24:42,720 --> 00:24:43,550 Na sasa nini jina lako tena? 694 00:24:43,550 --> 00:24:44,000 >> JASON: Jason. 695 00:24:44,000 --> 00:24:44,420 >> DAVID J. Malan: Jason. 696 00:24:44,420 --> 00:24:47,050 Hivyo sasa ni Jason ndogo kipengele nimekuwa kuchaguliwa. 697 00:24:47,050 --> 00:24:49,160 Ambapo ni yeye kwenda kwenda? 698 00:24:49,160 --> 00:24:50,380 Hivyo ambapo sita ni. 699 00:24:50,380 --> 00:24:51,210 Na jina lako ni tena? 700 00:24:51,210 --> 00:24:51,710 >> GABE: Gabe. 701 00:24:51,710 --> 00:24:52,340 >> DAVID J. Malan: Gabe. 702 00:24:52,340 --> 00:24:53,220 Gabe ni katika njia. 703 00:24:53,220 --> 00:24:54,640 Nini jambo rahisi kufanya? 704 00:24:54,640 --> 00:24:58,390 Wabadilishane guys hizi mbili na kuendelea. 705 00:24:58,390 --> 00:24:59,020 Hivyo sasa hebu angalia. 706 00:24:59,020 --> 00:25:00,170 Ambaye ni madogo? 707 00:25:00,170 --> 00:25:01,030 Nne. 708 00:25:01,030 --> 00:25:01,990 Hebu tu aina ya kudanganya. 709 00:25:01,990 --> 00:25:03,090 Tano ni kwenda kuwa ndogo. 710 00:25:03,090 --> 00:25:05,220 Mimi sioni ijayo, kama, unataka hatua mbele, je, mimi na kufanya na 711 00:25:05,220 --> 00:25:06,820 haya guys, na Gabe? 712 00:25:06,820 --> 00:25:08,450 Wabadilishane tena. 713 00:25:08,450 --> 00:25:10,740 Hivyo sasa, bado kidogo nje ya utaratibu. 714 00:25:10,740 --> 00:25:14,140 Nimeona Gabe kuwa ndogo, hivyo Mimi pop yake nje, hoja nyie juu. 715 00:25:14,140 --> 00:25:15,190 Na kufanyika. 716 00:25:15,190 --> 00:25:17,200 >> Hivyo jibu ni sawa. 717 00:25:17,200 --> 00:25:18,600 Matokeo ya mwisho ni moja. 718 00:25:18,600 --> 00:25:22,730 Ambayo ya algorithms hizi mbili ni bora? 719 00:25:22,730 --> 00:25:23,500 moja ya pili, nilisikia. 720 00:25:23,500 --> 00:25:24,252 Kwa nini? 721 00:25:24,252 --> 00:25:25,900 >> SPIKA 3: Ni hatua n [inaudible]. 722 00:25:25,900 --> 00:25:27,600 >> DAVID J. Malan: Ni hatua n saa zaidi. 723 00:25:27,600 --> 00:25:28,490 Kuvutia. 724 00:25:28,490 --> 00:25:30,610 Hivyo ni ingawa? 725 00:25:30,610 --> 00:25:33,630 Hivyo ni jinsi gani mimi kupata ndogo kipengele? 726 00:25:33,630 --> 00:25:37,060 Wangapi hatua gani mimi kuwa na kuchukua kupata kipengele madogo? 727 00:25:37,060 --> 00:25:39,220 Mimi nilikuwa na kuangalia njia yote mwishoni, haki? 728 00:25:39,220 --> 00:25:41,530 Kwa sababu katika hali mbaya zaidi kwamba, kile kama Neil walikuwa zaidi ya hapa? 729 00:25:41,530 --> 00:25:45,700 Hivyo tu kutafuta kipengele ndogo inachukua hatua yangu n, au n bala 1. 730 00:25:45,700 --> 00:25:46,100 Lakini, OK. 731 00:25:46,100 --> 00:25:46,980 Hivyo kurekebisha Neil. 732 00:25:46,980 --> 00:25:48,740 Kumbuka kwamba, dakika au hivyo iliyopita. 733 00:25:48,740 --> 00:25:51,680 >> Lakini jinsi gani mimi kupata ijayo ndogo kipengele? 734 00:25:51,680 --> 00:25:54,830 Ni n bala 1, au n bala 2 kwa kweli, kutoka kwa idadi ya hatua. 735 00:25:54,830 --> 00:25:55,440 Hivyo OK. 736 00:25:55,440 --> 00:25:57,390 Hivyo sikuweza n bala 2. 737 00:25:57,390 --> 00:25:57,600 Wote haki. 738 00:25:57,600 --> 00:25:59,130 Hivyo kwamba anahisi kidogo bora. 739 00:25:59,130 --> 00:25:59,730 Wote haki. 740 00:25:59,730 --> 00:26:03,270 Wangapi hatua wakati ujao kupata idadi tatu? 741 00:26:03,270 --> 00:26:04,420 Hivyo n minus 4. 742 00:26:04,420 --> 00:26:07,670 Hivyo ni kupungua, moja wachache hatua juu ya kila iteration. 743 00:26:07,670 --> 00:26:08,740 Hivyo hii haina kujisikia bora, haki? 744 00:26:08,740 --> 00:26:13,450 Kama mara ya mwisho ilikuwa ni takribani n mara n, wakati huu ni n minus 1, pamoja n bala 745 00:26:13,450 --> 00:26:16,500 2, pamoja n minus 3, pamoja n minus 4, dot, dot, dot. 746 00:26:16,500 --> 00:26:18,750 Lakini kama unakumbuka kutoka shule yako ya juu vitabu vya kiada, kudanganya kidogo 747 00:26:18,750 --> 00:26:24,380 karatasi ya nyuma ambayo ina kanuni, kama kuongeza up mfululizo huu wa namba, 748 00:26:24,380 --> 00:26:31,280 kile ni jumla ya idadi ya hatua kwenda kuwa kwamba mimi kuchukua hapa? 749 00:26:31,280 --> 00:26:36,580 >> Hii ni moja ya hizo, kama, n bala 1, nyakati n, kugawanywa na 2. 750 00:26:36,580 --> 00:26:39,040 Hivyo basi mimi kuona kama naweza kuvuta hili hadi kwa muda tu. 751 00:26:39,040 --> 00:26:42,230 Na tena, mimi nina aina ya rounding baadhi namba tu kuweka maisha yetu rahisi, 752 00:26:42,230 --> 00:26:47,830 lakini kama mimi kukumbuka, ni kitu kama kama Mimi kufanya n bala mambo 1, basi n bala 753 00:26:47,830 --> 00:26:53,570 2, basi n bala 3, ni takribani kitu kama hii zaidi ya 2, na kama mimi 754 00:26:53,570 --> 00:26:55,510 kuzidisha hii nje, hiyo ni kweli n mraba. 755 00:26:55,510 --> 00:26:58,940 Hiyo si hisia nzuri sana. n bala n zaidi ya 2. 756 00:26:58,940 --> 00:27:00,350 >> Lakini hapa ni kitu. 757 00:27:00,350 --> 00:27:03,720 Katika sayansi ya kompyuta, wakati matatizo kuanza kupata kuvutia ni wakati n 758 00:27:03,720 --> 00:27:04,700 anapata kweli kubwa. 759 00:27:04,700 --> 00:27:08,110 Na wakati n kweli anapata kubwa, ambayo ya maadili haya ni kwenda kutawala kila 760 00:27:08,110 --> 00:27:09,750 ya wengine? 761 00:27:09,750 --> 00:27:10,990 Ni aina ya n mraba, sawa? 762 00:27:10,990 --> 00:27:13,340 Ndiyo, kugawa na 2 ni nzuri. 763 00:27:13,340 --> 00:27:16,740 Lakini kama wewe ni kuzungumza juu ya mabilioni ya vipande vya data, au matrilioni ya 764 00:27:16,740 --> 00:27:18,700 vipande ya data, OK, hivyo wewe ni mara mbili kwa haraka. 765 00:27:18,700 --> 00:27:22,440 Lakini ambao kwa kweli wasiwasi kama idadi kuwa kubwa, kama sababu hii ni nini anapata 766 00:27:22,440 --> 00:27:23,040 makubwa na kubwa. 767 00:27:23,040 --> 00:27:25,990 Na hakika, inafanya zaidi ya tofauti kuliko guy. 768 00:27:25,990 --> 00:27:29,120 Hivyo hata kama nyie ni haki, pili algorithm, tutaweza kuiita 769 00:27:29,120 --> 00:27:32,970 uteuzi aina, ni, katika ulimwengu wa kweli, kidogo kwa kasi uwezekano, kwa sababu mimi ni 770 00:27:32,970 --> 00:27:35,360 kuchukua chache na chache hatua kila wakati. 771 00:27:35,360 --> 00:27:37,340 >> Ni kweli kimsingi kwa kasi zaidi. 772 00:27:37,340 --> 00:27:41,430 Kwa sababu kama sisi kweli kucheza nje kwa ajili ya kubwa maadili ya n, mwishoni mwa 773 00:27:41,430 --> 00:27:44,750 siku, kwa ajili ya n kubwa ya kutosha, bado kwenda kujisikia pretty polepole. 774 00:27:44,750 --> 00:27:46,770 Naam, napenda kuchukua moja mwisho kupita saa hiyo. 775 00:27:46,770 --> 00:27:48,920 Hiyo ni nini napenda kuita uteuzi aina. 776 00:27:48,920 --> 00:27:51,040 Unaweza guys upya wenyewe mara moja ya mwisho? 777 00:27:51,040 --> 00:27:53,550 Na katika kesi hii ya mwisho, mimi naenda kupendekeza kitu 778 00:27:53,550 --> 00:27:54,970 kuitwa kuingizwa aina. 779 00:27:54,970 --> 00:27:57,470 Kuingizwa aina kuwa, conceptually, tofauti kidogo. 780 00:27:57,470 --> 00:28:00,980 >> Badala ya kwenda na kurudi na kuchagua kipengele ndogo, mimi nina 781 00:28:00,980 --> 00:28:05,030 tu kwenda kukabiliana na kila moja ya haya guys kama mimi kukutana nao, na kuingiza 782 00:28:05,030 --> 00:28:06,850 yao katika nafasi yao sahihi. 783 00:28:06,850 --> 00:28:10,160 Hivyo nina kwenda tu kuanza na neema, na mimi kuona kwamba yeye ni namba nne. 784 00:28:10,160 --> 00:28:11,720 Ambapo haina namba nne ni mali? 785 00:28:11,720 --> 00:28:14,940 Mimi si kuanza kuchagua kitu chochote, hivyo Grace anapata haki ya kukaa huko. 786 00:28:14,940 --> 00:28:18,355 Na sasa mimi nina kwenda kudai, kama unaweza kuchukua hatua ya haki yako, hii 787 00:28:18,355 --> 00:28:21,650 orodha yangu sorted, hii ni yangu zisizochambuliwa iliyobaki orodha. 788 00:28:21,650 --> 00:28:23,260 Hivyo sasa mimi naenda kuendelea ijayo, na nini jina lako tena? 789 00:28:23,260 --> 00:28:23,700 >> BRANSON: Branson. 790 00:28:23,700 --> 00:28:24,150 >> DAVID J. Malan: Branson. 791 00:28:24,150 --> 00:28:25,375 Hivyo Branson ni namba mbili. 792 00:28:25,375 --> 00:28:27,490 Hivyo nina kwenda kuchukua wewe nje kwa muda. 793 00:28:27,490 --> 00:28:30,940 Na sasa, wapi ni mali ya katika safu hii? 794 00:28:30,940 --> 00:28:32,360 Hivyo haki ya Neema. 795 00:28:32,360 --> 00:28:35,670 Hivyo tena, sisi ni aina ya maamuzi Neema kufanya mengi ya kazi hapa. 796 00:28:35,670 --> 00:28:37,290 Wapi sisi kuweka wewe? 797 00:28:37,290 --> 00:28:40,120 Hivyo sisi ni kwenda kwa slide wewe kushoto, na kuingiza Branson huko. 798 00:28:40,120 --> 00:28:41,680 Lakini sasa mimi kudai kwamba nyie ni kufanyika. 799 00:28:41,680 --> 00:28:43,240 Lakini sikia, mimi si kutumia nafasi ya ziada. 800 00:28:43,240 --> 00:28:45,130 Ni bado 2 vipengele hapa, 5 zaidi ya hapa. 801 00:28:45,130 --> 00:28:47,910 Jumla ya safu ya kawaida ni 7, hivyo mimi nina si cheating, wote haki? 802 00:28:47,910 --> 00:28:51,950 >> Hivyo sasa sisi, na Gabe hapa, namba sita, wapi ni mali? 803 00:28:51,950 --> 00:28:52,650 You got bahati tena. 804 00:28:52,650 --> 00:28:53,820 Hivyo kupata haki ya kukaa huko. 805 00:28:53,820 --> 00:28:57,210 Tu kuchukua hatua kidogo kwa haki tu kufanya wazi kwamba wewe ni Iliyopangwa. 806 00:28:57,210 --> 00:29:00,520 Na sasa tuna Neil tena, idadi moja, wapi kwenda? 807 00:29:00,520 --> 00:29:03,540 Na sasa ni ambapo tutaweza kuanza kuona kwamba hii algorithm, ingawa siku ya kwanza 808 00:29:03,540 --> 00:29:05,950 mtazamo, anahisi pretty smart, kuangalia nini kuhusu kutokea. 809 00:29:05,950 --> 00:29:07,370 Kama unaweza hatua mbele. 810 00:29:07,370 --> 00:29:09,260 >> Wapi tunataka kuweka Neil? 811 00:29:09,260 --> 00:29:11,830 Hivyo ni wazi hapa, hivyo ni jinsi tunapata Neil huko? 812 00:29:11,830 --> 00:29:12,970 Hebu kufanya hivyo hatua kwa hatua. 813 00:29:12,970 --> 00:29:15,620 Gabe, wapi unahitaji kwenda? 814 00:29:15,620 --> 00:29:19,590 Yep, hivyo kuchukua hatua moja kubwa, au mbili nusu-hatua ya kufanya 815 00:29:19,590 --> 00:29:20,820 hatua moja zaidi ya hapo. 816 00:29:20,820 --> 00:29:21,750 Neema, ambapo kwenda? 817 00:29:21,750 --> 00:29:22,510 Nzuri. 818 00:29:22,510 --> 00:29:23,500 Hivyo hatua nyingine. 819 00:29:23,500 --> 00:29:24,960 Na hatimaye, Branson? 820 00:29:24,960 --> 00:29:25,460 Hatua nyingine. 821 00:29:25,460 --> 00:29:27,190 Na sasa tunaweza kuweka Neil katika nafasi. 822 00:29:27,190 --> 00:29:28,440 >> Hivyo sasa, kuendelea mantiki hii. 823 00:29:28,440 --> 00:29:32,420 Hata kama sisi si shifting Neil tena na tena, na tena, kwa kumtia 824 00:29:32,420 --> 00:29:36,420 aendako, katika kesi mbaya, ijayo idadi tuweze kukutana hawakuweza 825 00:29:36,420 --> 00:29:42,220 kuwa idadi, kusema, kulikuwa na idadi sifuri, kisha tunakwenda kuhama yote ya 826 00:29:42,220 --> 00:29:42,730 haya guys. 827 00:29:42,730 --> 00:29:44,950 Tuseme kwamba kuna idadi, hasi moja, basi tuna kuhama 828 00:29:44,950 --> 00:29:46,080 wote wa guys hawa. 829 00:29:46,080 --> 00:29:48,500 Hivyo sisi ni kweli tu aina ya flipping tatizo kote, kwamba vile tuko 830 00:29:48,500 --> 00:29:52,620 kuhamisha gharama kutoka uteuzi mchakato ili kuingizwa 831 00:29:52,620 --> 00:29:56,930 mchakato, kama kwamba nyie tu alikuwa kwa hoja takribani n bala kitu 832 00:29:56,930 --> 00:29:57,940 Idadi ya hatua. 833 00:29:57,940 --> 00:30:01,200 Na kwamba idadi ya hatua ni kwenda tu kuongeza kama mimi kuchagua idadi zaidi, 834 00:30:01,200 --> 00:30:04,730 kama mimi na kuweka msukumano nyie nyuma, na nyuma, na nyuma. 835 00:30:04,730 --> 00:30:08,320 >> Hivyo jambo la kusikitisha sasa ni yote haya algorithms ni n squared. 836 00:30:08,320 --> 00:30:10,570 Hebu kwenda mbele na shukrani kwa hizi guys, na taswira hizi kidogo 837 00:30:10,570 --> 00:30:11,090 tofauti. 838 00:30:11,090 --> 00:30:12,312 Vizuri sana kufanyika. 839 00:30:12,312 --> 00:30:14,120 >> [Makofi] 840 00:30:14,120 --> 00:30:15,030 >> Wote haki. 841 00:30:15,030 --> 00:30:16,280 Kuna kwenda. 842 00:30:16,280 --> 00:30:18,390 843 00:30:18,390 --> 00:30:18,470 Shukrani kwa ajili ya - 844 00:30:18,470 --> 00:30:19,190 >> BRANSON: [inaudible] kushika namba. 845 00:30:19,190 --> 00:30:21,990 >> DAVID J. Malan: Hapana, unaweza kuweka idadi pia. 846 00:30:21,990 --> 00:30:23,440 Wote haki. 847 00:30:23,440 --> 00:30:24,100 Nicely kufanyika. 848 00:30:24,100 --> 00:30:25,300 Wote haki. 849 00:30:25,300 --> 00:30:30,510 Basi hebu angalia kama hatuwezi sasa muhtasari haraka zaidi, na zaidi kuibua, 850 00:30:30,510 --> 00:30:33,410 nini hasa ilitokea tu hapa kama ifuatavyo. 851 00:30:33,410 --> 00:30:36,510 852 00:30:36,510 --> 00:30:38,770 Mimi nina kwenda mbele na kuvuta Firefox. 853 00:30:38,770 --> 00:30:41,310 Tutaweza kuhusisha maandamano haya kwenye tovuti ya kozi ya. 854 00:30:41,310 --> 00:30:43,870 Java ni kidogo annoying kupata kazi katika baadhi ya browsers siku hizi. 855 00:30:43,870 --> 00:30:46,760 Hivyo kama huna kucheza na hili nyumbani, kutambua unaweza haja ya kutumia Firefox 856 00:30:46,760 --> 00:30:47,990 kupata kazi. 857 00:30:47,990 --> 00:30:50,440 Na kile Mimi naenda kufanya na hii maandamano ni yafuatayo. 858 00:30:50,440 --> 00:30:54,875 >> Chini, nina rundo zima la orodha ya chaguzi, ikiwa ni pamoja na kuanza na 859 00:30:54,875 --> 00:30:55,840 kuacha kifungo. 860 00:30:55,840 --> 00:30:59,450 Pia, kama kando, inaonekana kuna mdudu katika programu hizi, ambapo wewe 861 00:30:59,450 --> 00:31:03,720 hawawezi kweli kuona kuanza au kuacha kifungo isipokuwa wewe kushikilia amri au Alt 862 00:31:03,720 --> 00:31:06,560 pamoja na kuvuta, ambayo ajabu inaonyesha wewe vifungo zaidi. 863 00:31:06,560 --> 00:31:09,090 Hivyo tu FYI kama wewe kucheza na hii nyumbani. 864 00:31:09,090 --> 00:31:12,870 Sasa mimi nina kwenda bonyeza Start katika tu huu, baada ya kubainisha kuchelewa, 865 00:31:12,870 --> 00:31:16,810 kama, 200 milisekunde hapa, tu ili tuweze kuona nini kinatokea. 866 00:31:16,810 --> 00:31:20,180 >> Hivyo mimi kudai kwamba hii ni taswira ya algorithm ya kwanza 867 00:31:20,180 --> 00:31:23,730 haya guys alivyofanya, Bubble aina, ambapo sisi walibadilishana watu jozi-busara. 868 00:31:23,730 --> 00:31:27,490 ufahamu muhimu kwa taswira hii ni kwamba urefu wa baa 869 00:31:27,490 --> 00:31:30,510 inawakilisha ukubwa wa idadi. 870 00:31:30,510 --> 00:31:32,210 Hivyo mirefu bar, kubwa ya simu. 871 00:31:32,210 --> 00:31:33,680 Mfupi bar, ndogo idadi. 872 00:31:33,680 --> 00:31:38,630 Na kama taarifa, tunakwenda kupitia iteration ya kwanza ya algorithm hii, 873 00:31:38,630 --> 00:31:42,620 swapping idadi kubwa na ndogo, hivyo kwamba idadi ndogo huja kwanza na 874 00:31:42,620 --> 00:31:44,280 idadi kubwa huenda kwa haki. 875 00:31:44,280 --> 00:31:48,770 >> Na kwa haraka kama sisi kupata mwisho wa safu ya idadi ya watu wengi zaidi ya saba, sisi ni 876 00:31:48,770 --> 00:31:49,900 kwenda nyuma ya mwanzo. 877 00:31:49,900 --> 00:31:51,140 Na wanatarajia hii. 878 00:31:51,140 --> 00:31:54,860 Juu ya mbali kushoto, guy kidogo kinaendelea wabadilishane kwa upande, na hii 879 00:31:54,860 --> 00:31:56,010 mchakato wa kurudia. 880 00:31:56,010 --> 00:31:59,450 Sasa taswira hii haraka anapata boring, hivyo napenda kwenda mbele na kuacha 881 00:31:59,450 --> 00:32:04,170 hivyo, mabadiliko ya kitu kuchelewa kasi tu kupata sasa, kujisikia kwa ajili ya 882 00:32:04,170 --> 00:32:05,060 hii algorithm. 883 00:32:05,060 --> 00:32:07,840 >> Hivyo ingawa nimekuwa sped it up, hii ni kama kuwaendeleza processor yangu, kununua 884 00:32:07,840 --> 00:32:08,580 kompyuta mpya. 885 00:32:08,580 --> 00:32:12,980 Mimi si kimsingi iliyopita yangu algorithm, lakini unaweza kweli kuona zaidi 886 00:32:12,980 --> 00:32:16,800 uwazi kuliko na binadamu, kuwa kubwa idadi ni bubbling hadi juu, 887 00:32:16,800 --> 00:32:20,900 na idadi ndogo ni bubbling chini kwa chini. 888 00:32:20,900 --> 00:32:22,390 Na sasa jambo hili hapa Iliyopangwa. 889 00:32:22,390 --> 00:32:25,260 Na kama kando, katika viwanja, kuna baadhi tu bookkeeping huko 890 00:32:25,260 --> 00:32:28,010 kukusaidia kulinganisha hesabu ngapi, au wangapi swaps na 891 00:32:28,010 --> 00:32:28,950 kweli imekuwa kufanyika. 892 00:32:28,950 --> 00:32:30,750 >> Naam, hebu kujaribu moja ya wengine tuliona. 893 00:32:30,750 --> 00:32:37,116 Hebu bonyeza aina Bubble hapa, na basi mimi kuchagua, na hii yote ukurasa wa mtandao 894 00:32:37,116 --> 00:32:38,936 ni Buggy kidogo. 895 00:32:38,936 --> 00:32:41,155 Hebu kukubali hatari na kukimbia tena. 896 00:32:41,155 --> 00:32:44,560 897 00:32:44,560 --> 00:32:45,030 Kuna sisi kwenda. 898 00:32:45,030 --> 00:32:47,180 Basi hebu kufanya uteuzi aina. 899 00:32:47,180 --> 00:32:49,140 Sijui kwa nini orodha ya inaonekana zaidi ya hapo. 900 00:32:49,140 --> 00:32:54,070 Hebu zoom katika kurekebisha kwamba mdudu, mabadiliko haya ya 50. 901 00:32:54,070 --> 00:32:56,020 Ah, hebu kweli kufanya kwamba kwa kasi zaidi. 902 00:32:56,020 --> 00:32:59,160 Tano milisekunde au hivyo, na Anza. 903 00:32:59,160 --> 00:33:00,470 >> Hivyo hii ni uteuzi aina. 904 00:33:00,470 --> 00:33:03,070 Hivyo tena, kufikiri juu ya nini sisi alivyofanya kwa binadamu hapa juu. 905 00:33:03,070 --> 00:33:08,490 Tulikwenda kupitia safu na kuchaguliwa kipengele ndogo tena, 906 00:33:08,490 --> 00:33:09,250 na tena, na tena. 907 00:33:09,250 --> 00:33:11,110 Sasa mimi kudai kwamba alikuwa bado pretty mbaya. 908 00:33:11,110 --> 00:33:15,010 Ilikuwa bado n squared, kutoa au kuchukua, lakini ilikuwa, katika ulimwengu wa kweli, kidogo 909 00:33:15,010 --> 00:33:18,280 kasi, kwa sababu mimi nilikuwa kwa kweli kuchukua kidogo wachache hatua kila wakati. 910 00:33:18,280 --> 00:33:19,800 Lakini sisi ni tu kuzungumza nini? 911 00:33:19,800 --> 00:33:21,830 Labda 40 au hivyo baa hapa? 912 00:33:21,830 --> 00:33:23,200 Hatuzungumzii milioni 40. 913 00:33:23,200 --> 00:33:27,430 Hivyo si wazi kabisa kwangu kwamba kweli alikuwa faida kubwa. 914 00:33:27,430 --> 00:33:32,530 >> Sasa niende nyuma na kubadili kwa wetu tatu algorithm, ambayo ilikuwa kuchagua 915 00:33:32,530 --> 00:33:33,180 kuingizwa aina. 916 00:33:33,180 --> 00:33:36,380 Na sasa ni kweli kwa sababu Buggy orodha ya kweli haipaswi kuwa chini huko. 917 00:33:36,380 --> 00:33:40,840 Hivyo sasa tutaweza kitabu nyuma hadi hapa na kuanza hii algorithm. 918 00:33:40,840 --> 00:33:43,270 Whoop, kuanza na kuacha. 919 00:33:43,270 --> 00:33:47,160 Hivyo hii aina moja ya ina muundo mzuri hiyo, ambapo sisi ni tena 920 00:33:47,160 --> 00:33:50,240 kuingiza binadamu, au katika kesi hii, baa katika 921 00:33:50,240 --> 00:33:52,620 eneo lao sahihi. 922 00:33:52,620 --> 00:33:55,430 Na ni tayari kufanyika kabla ya Mimi akageuka. 923 00:33:55,430 --> 00:33:58,940 Lakini hii moja, pia, katika nadharia, bado ni n squared. 924 00:33:58,940 --> 00:34:01,430 >> Basi hebu angalia kama hatuwezi kufupisha haya kama ifuatavyo. 925 00:34:01,430 --> 00:34:04,750 Mimi nina kwenda mbele na tu kutoa sisi aina ya njia ya kawaida ya kuzungumza 926 00:34:04,750 --> 00:34:08,489 kuhusu mambo haya, basi mimi kuanzisha kidogo tu ya nukuu hapa. 927 00:34:08,489 --> 00:34:12,480 Uko juu ya kuona kitu kinachoitwa kubwa O, kwa sababu ni kubwa halisi 928 00:34:12,480 --> 00:34:16,320 O. Na hii ni njia ambayo kompyuta mwanasayansi au mtaalamu wa hisabati hata anatumia 929 00:34:16,320 --> 00:34:19,230 kuelezea wakati mbio ya algorithm baadhi. 930 00:34:19,230 --> 00:34:21,400 Jinsi gani hatua nyingi kweli kuchukua? 931 00:34:21,400 --> 00:34:25,080 >> Sasa mimi nina kwenda embarrass mwenyewe na mwandiko wangu hapa katika muda tu. 932 00:34:25,080 --> 00:34:29,020 Lakini napenda kwenda mbele na kusema kwamba hii itakuwa kubwa O zaidi ya hapa. 933 00:34:29,020 --> 00:34:33,610 Na napenda kuanzisha nyingine moja ishara, omega mji mkuu. 934 00:34:33,610 --> 00:34:37,080 Omega ni kwenda kuwa kinyume, kimsingi, ya kubwa O. Wakati kubwa O 935 00:34:37,080 --> 00:34:40,790 maana, katika kesi mbaya, ni kiasi gani wakati wapate algorithm baadhi ya kuchukua, katika 936 00:34:40,790 --> 00:34:43,480 suala la n, omega ni kwenda kuwa na muda kiasi gani ili ni 937 00:34:43,480 --> 00:34:45,409 kuchukua katika kesi bora. 938 00:34:45,409 --> 00:34:48,090 Na tutaweza kuona nini maana sisi na bora kesi katika muda tu. 939 00:34:48,090 --> 00:34:49,940 >> Basi hebu kuanza kitu rahisi. 940 00:34:49,940 --> 00:34:54,719 Napenda kuanza kwa tafuta linear. 941 00:34:54,719 --> 00:34:55,679 Hivyo si kuchagua. 942 00:34:55,679 --> 00:34:58,000 Tutamwita hii tafuta linear. 943 00:34:58,000 --> 00:35:01,140 Na sasa, kufanya kidogo meza nje ya hili. 944 00:35:01,140 --> 00:35:06,600 Na sasa, katika kesi ya tafuta linear, katika hali mbaya, jinsi hatua nyingi ni 945 00:35:06,600 --> 00:35:11,770 ni kwenda kuchukua mimi kupata simu ya uchaguzi kiholela? 946 00:35:11,770 --> 00:35:14,540 Na kuna n milango taarifa au n idadi ya jumla. 947 00:35:14,540 --> 00:35:15,940 Kesi mbaya. 948 00:35:15,940 --> 00:35:18,800 Jinsi hatua nyingi mimi kwenda na kuchukua ili kupata nambari 50 katika safu 949 00:35:18,800 --> 00:35:20,830 ya n milango? 950 00:35:20,830 --> 00:35:21,410 Na kwa nini? 951 00:35:21,410 --> 00:35:23,680 Kwa sababu inaweza kuwa kila njia juu kwenye mwisho. 952 00:35:23,680 --> 00:35:27,120 Sana kama Jennifer wamekutana, simu 50 ilikuwa njia yote juu, hivyo katika 953 00:35:27,120 --> 00:35:30,760 kesi mbaya linear tafuta ni kubwa O ya n, tutaweza kusema. 954 00:35:30,760 --> 00:35:33,430 >> Nini kuhusu kesi bora, kama kupata kweli bahati? 955 00:35:33,430 --> 00:35:36,200 Ni tu kwenda kuchukua hatua moja, au simu mara kwa mara ya hatua. 956 00:35:36,200 --> 00:35:37,830 Hivyo tutaweza kuelezea kwamba kama 1. 957 00:35:37,830 --> 00:35:39,010 Hivyo hii ni nzuri sana. 958 00:35:39,010 --> 00:35:41,210 Sasa nini kama sisi alifanya kitu kama tafuta binary? 959 00:35:41,210 --> 00:35:43,860 960 00:35:43,860 --> 00:35:47,846 Hivyo binary tafuta, katika mbaya kesi, alichukua muda gani? 961 00:35:47,846 --> 00:35:49,250 >> [INTERPOSING SAUTI] 962 00:35:49,250 --> 00:35:51,310 >> DAVID J. Malan: Hivyo kwa kweli, mimi habari hiyo katika maeneo ya wanandoa. 963 00:35:51,310 --> 00:35:56,390 Hivyo ni kweli kuingia n, kutoa au kuchukua, kwa sababu kama sisi kugawanya orodha katika nusu 964 00:35:56,390 --> 00:36:00,730 tena, na tena, na tena, sisi ni uwezo kupata, hatimaye, thamani, 965 00:36:00,730 --> 00:36:04,750 kama ni pale, lakini kuna samaki. 966 00:36:04,750 --> 00:36:08,590 Nini dhana kwamba tuna kuchukua kwa nafasi kwa ajili ya kutafuta binary? 967 00:36:08,590 --> 00:36:09,700 Ina ya kutatuliwa. 968 00:36:09,700 --> 00:36:12,770 Siyo sorted, unaweza kupasuliwa jambo katika nusu ya tena na tena, na wewe 969 00:36:12,770 --> 00:36:15,490 unaweza kwenda kushoto, na unaweza kwenda kulia, na unaweza kwenda kushoto na kulia, lakini wewe ni 970 00:36:15,490 --> 00:36:18,070 si kwenda kupata kipengele kama orodha si vyema, kwa sababu 971 00:36:18,070 --> 00:36:18,790 unaweza miss it. 972 00:36:18,790 --> 00:36:22,120 Sababu heuristic yako, kwa ajili ya kwenda kushoto au haki ni kwenda kuwa kiujanja kama ni 973 00:36:22,120 --> 00:36:23,420 kweli si vyema. 974 00:36:23,420 --> 00:36:26,110 Hivyo kuna aina ya gharama za siri kwa kutumia kitu kama hiki. 975 00:36:26,110 --> 00:36:29,250 >> Sasa, hebu kwenda katika kuchagua wetu algorithms si kutafuta - 976 00:36:29,250 --> 00:36:31,140 oh, kwa kweli hebu kwenda katika tupu hii. 977 00:36:31,140 --> 00:36:33,190 Binary tafuta katika kesi bora? 978 00:36:33,190 --> 00:36:36,290 Ni pia 1 kama ni hutokea tu kuwa katika sana katikati ya safu, au 979 00:36:36,290 --> 00:36:37,810 katikati ya kitabu cha simu. 980 00:36:37,810 --> 00:36:39,710 Sasa hebu kufanya Bubble aina. 981 00:36:39,710 --> 00:36:42,570 Hivyo tena, sasa sisi ni kuingia kila aina, si upekuzi. 982 00:36:42,570 --> 00:36:47,220 >> Katika hali mbaya zaidi, jinsi hatua nyingi hatukufanya madai Bubble aina kwenda kuchukua? 983 00:36:47,220 --> 00:36:48,410 n squared. 984 00:36:48,410 --> 00:36:49,200 Hivyo nina kwenda kuteka kwamba. 985 00:36:49,200 --> 00:36:51,710 Ooh, mwandiko wangu inaonekana mbaya zaidi wakati ni makadirio kuwa kubwa. 986 00:36:51,710 --> 00:36:52,510 Wote haki. 987 00:36:52,510 --> 00:36:53,570 Hivyo hiyo n squared. 988 00:36:53,570 --> 00:36:59,460 Na katika kesi bora wa aina Bubble, jinsi hatua nyingi ni kwenda kuchukua? 989 00:36:59,460 --> 00:37:00,980 1, nikasikia. 990 00:37:00,980 --> 00:37:01,760 >> SPIKA 1: n. 991 00:37:01,760 --> 00:37:03,286 >> DAVID J. Malan: n, nikasikia. 992 00:37:03,286 --> 00:37:04,200 >> SPIKA 1: 2. 993 00:37:04,200 --> 00:37:05,010 >> DAVID J. Malan: 2, nikasikia. 994 00:37:05,010 --> 00:37:06,670 Je, mimi kusikia 3? 995 00:37:06,670 --> 00:37:07,080 Wote haki. 996 00:37:07,080 --> 00:37:11,390 Hivyo Nimesikia 1, n, 2, lakini hebu kuchukua mbali angalau kwanza ya wale 997 00:37:11,390 --> 00:37:12,330 mapendekezo, 1. 998 00:37:12,330 --> 00:37:15,370 Siyo silika mbaya, kwa sababu ni aina ya muundo hapa ifuatavyo. 999 00:37:15,370 --> 00:37:19,670 Lakini kama tu inachukua 1 hatua, jinsi katika dunia inaweza mimi kudai kwamba orodha 1000 00:37:19,670 --> 00:37:22,900 ni Iliyopangwa, kwa sababu kama mimi nina kuruhusiwa tu kuchukua hatua ya 1, jinsi mambo mengi 1001 00:37:22,900 --> 00:37:25,230 inaweza mimi kwa kweli kuangalia kuwa na uhakika? 1002 00:37:25,230 --> 00:37:28,270 Naam, 1 tu, ambayo ina maana kuna n bala vipengele 1 ambayo inaweza kuwa nje ya 1003 00:37:28,270 --> 00:37:31,310 ili, na Mimi tu kwenda juu ya imani baada ya kuangalia kipengele 1 kwamba 1004 00:37:31,310 --> 00:37:31,850 kitu ni Iliyopangwa. 1005 00:37:31,850 --> 00:37:33,930 Hivyo 1 siyo sahihi hapa. 1006 00:37:33,930 --> 00:37:35,710 Hivyo chini, wangapi mimi na kuangalia? 1007 00:37:35,710 --> 00:37:36,680 >> [INTERPOSING SAUTI] 1008 00:37:36,680 --> 00:37:40,160 >> DAVID J. Malan: n minus 1, au kweli, n, kwa sababu mimi haja ya kuangalia kila 1009 00:37:40,160 --> 00:37:42,190 kipengele kuhakikisha kwamba siyo nje ya utaratibu. 1010 00:37:42,190 --> 00:37:44,750 Lakini tena, tutaweza aina ya wimbi wetu mikono wakati idadi ndogo na 1011 00:37:44,750 --> 00:37:47,100 kudhani kwamba, kama n anapata kubwa, wao ni uninteresting anyway. 1012 00:37:47,100 --> 00:37:48,380 Hivyo kwamba ni Bubble aina. 1013 00:37:48,380 --> 00:37:49,830 Na sasa, hebu kufanya hizi mbili za mwisho. 1014 00:37:49,830 --> 00:37:53,520 Uteuzi aina, na kisha tutaweza kufanya kuingizwa aina. 1015 00:37:53,520 --> 00:37:57,160 Na kisha sisi pigo yako akili na kitu gani 1016 00:37:57,160 --> 00:37:58,926 bora kuliko yote haya. 1017 00:37:58,926 --> 00:38:00,410 Wote haki. 1018 00:38:00,410 --> 00:38:04,700 >> Je, ni kesi mbaya mbio wakati wa aina uteuzi? 1019 00:38:04,700 --> 00:38:05,680 >> SPIKA 4: n squared. 1020 00:38:05,680 --> 00:38:06,710 >> DAVID J. Malan: n mraba, mimi nina kusikia. 1021 00:38:06,710 --> 00:38:09,790 Lakini kwa nini n squared, intuitively? 1022 00:38:09,790 --> 00:38:11,170 >> SPIKA 4: Kwa sababu sisi tu alifanya hivyo. 1023 00:38:11,170 --> 00:38:12,260 >> DAVID J. Malan: Kwa sababu sisi tu alifanya hivyo. 1024 00:38:12,260 --> 00:38:12,550 OK. 1025 00:38:12,550 --> 00:38:13,380 Nzuri jibu. 1026 00:38:13,380 --> 00:38:16,660 Lakini shirikishi, kwa nini ni uteuzi aina n squared? 1027 00:38:16,660 --> 00:38:18,980 Nini sisi kufanya tena na tena? 1028 00:38:18,980 --> 00:38:22,570 Tulikuwa na kuweka skanning kupitia, ni wewe ndogo, ni wewe 1029 00:38:22,570 --> 00:38:24,020 ndogo, wewe ni ndogo. 1030 00:38:24,020 --> 00:38:27,480 Na nafasi, tulikuwa na uwezo wa kuchukua n hatua, basi n bala 1, basi n bala 2. 1031 00:38:27,480 --> 00:38:30,700 Lakini kama wewe aina ya kuongeza wale wote juu, au kuchukua ni juu ya imani kwamba nimepata aliongeza 1032 00:38:30,700 --> 00:38:34,810 yao juu mapema, sisi kupata takribani n squared bala idadi ya baadhi vidogo vidogo. 1033 00:38:34,810 --> 00:38:36,730 Hivyo nina kwenda kuwaita n hii squared. 1034 00:38:36,730 --> 00:38:39,530 Lakini pamoja na uteuzi aina bora katika kesi, jinsi hatua nyingi ni 1035 00:38:39,530 --> 00:38:40,632 kwenda kuchukua mimi? 1036 00:38:40,632 --> 00:38:41,840 >> SPIKA 5: [inaudible] 1037 00:38:41,840 --> 00:38:44,350 >> DAVID J. Malan: Ni kwa bahati mbaya bado n mraba, sawa? 1038 00:38:44,350 --> 00:38:49,590 Kwa sababu kama mimi nina kuchagua ndogo kipengele, na tulikuwa watu saba hapa, 1039 00:38:49,590 --> 00:38:53,280 Mimi tu kujua, mara moja mimi kupata sana mwisho, kwamba Nimepata ndogo 1040 00:38:53,280 --> 00:38:55,670 simu, popote yeye au anaweza wamekuwa. 1041 00:38:55,670 --> 00:38:58,820 Lakini jinsi gani mimi kupata ijayo idadi ndogo? 1042 00:38:58,820 --> 00:39:00,160 Mimi kufanya mwingine kupita. 1043 00:39:00,160 --> 00:39:04,810 Hivyo katika kesi bora, ni nini pembejeo kwa aina uteuzi? 1044 00:39:04,810 --> 00:39:07,830 Ni tayari aina orodha, namba moja, namba mbili, namba tatu, namba nne. 1045 00:39:07,830 --> 00:39:08,600 Lakini mimi nina kompyuta. 1046 00:39:08,600 --> 00:39:10,190 Naweza tu kuangalia moja jambo kwa wakati. 1047 00:39:10,190 --> 00:39:12,465 Siwezi aina ya kuchukua hatua ya nyuma kama binadamu na kusema, 1048 00:39:12,465 --> 00:39:14,030 ooh, hii inaonekana sahihi. 1049 00:39:14,030 --> 00:39:17,580 >> Naweza tu adjudicate usahihi katika uteuzi aina kwa kuchagua 1050 00:39:17,580 --> 00:39:18,370 idadi ndogo. 1051 00:39:18,370 --> 00:39:21,390 Lakini hata kama mimi kupata simu moja ya kwanza, kama mimi sijui kitu kingine kuhusu 1052 00:39:21,390 --> 00:39:24,460 idadi nyingine, ambayo mimi si, wote mimi kujua kwamba nimekuwa mitupu safu 1053 00:39:24,460 --> 00:39:27,930 au seti ya milango ya nyuma ambayo ni namba, njia pekee ya mimi kujua kwamba mtu 1054 00:39:27,930 --> 00:39:28,680 ilikuwa ndogo? 1055 00:39:28,680 --> 00:39:32,440 Kama mimi kupata njia yote hapa na kutambua, damn, moja ilikuwa kweli ndogo. 1056 00:39:32,440 --> 00:39:34,870 >> Lakini jinsi gani mimi kisha kuamua kwamba wawili ni ndogo ijayo? 1057 00:39:34,870 --> 00:39:38,350 Kwa kufanya uzembe huo tena na tena. 1058 00:39:38,350 --> 00:39:42,210 Hivyo hatimaye, na aina ya kuingizwa, jinsi gani, katika hali mbaya zaidi, 1059 00:39:42,210 --> 00:39:44,990 gani sisi kusema hufanya? 1060 00:39:44,990 --> 00:39:49,100 Hiyo pia ni n squared. 1061 00:39:49,100 --> 00:39:53,020 Na vipi kuhusu na kesi bora? 1062 00:39:53,020 --> 00:39:56,282 Tutaweza kuondoka kwamba kama cliffhanger. 1063 00:39:56,282 --> 00:40:00,090 Tutaweza kujaza wakati huo tupu ijayo, lakini niruhusu kwanza kupendekeza kwamba sisi 1064 00:40:00,090 --> 00:40:02,620 kimsingi kufanya vizuri zaidi kuliko yote haya, wote haki? 1065 00:40:02,620 --> 00:40:05,220 >> Hivyo kufikiri mwenyewe nini kuingizwa aina kwenda kuwa. 1066 00:40:05,220 --> 00:40:06,910 Naam, hilo si makubwa sana, kwa sababu mimi nina moja tu 1067 00:40:06,910 --> 00:40:08,970 kwamba aliona mabadiliko. 1068 00:40:08,970 --> 00:40:09,620 Wow. 1069 00:40:09,620 --> 00:40:10,420 OK. 1070 00:40:10,420 --> 00:40:12,615 Hivyo hapa tuna kiasi fulani tofauti maandamano. 1071 00:40:12,615 --> 00:40:16,580 Kama mimi kuvuta hapa, utaona kwamba kwenye kushoto tuna Bubble aina, katika 1072 00:40:16,580 --> 00:40:20,740 katikati tuna uteuzi aina, na juu ya haki ya mbali, tuna kitu sisi 1073 00:40:20,740 --> 00:40:23,380 si inaonekana saa bado kuitwa kuunganisha aina. 1074 00:40:23,380 --> 00:40:26,080 Lakini fikiria nini tumekuwa kufanya hapa hivi sasa leo. 1075 00:40:26,080 --> 00:40:29,200 Wakati Jennifer kwanza alikuja juu ya hatua, tulikwenda kupitia safu ya idadi 1076 00:40:29,200 --> 00:40:33,750 tena, na tena, na tafuta linear, na tulipata linear mbio wakati, kubwa O 1077 00:40:33,750 --> 00:40:35,100 ya n, hivyo kusema. 1078 00:40:35,100 --> 00:40:41,000 >> Wakati sisi sasa kufikiria wiki ya kwanza ya darasa, wakati tulikuwa kugawanya na kushinda, 1079 00:40:41,000 --> 00:40:43,740 na tulikuwa na kitabu cha simu akamtikisatikisa, na Jennifer, na sisi kwa pamoja 1080 00:40:43,740 --> 00:40:47,500 leveraged kwamba muhimu ufahamu, ambayo ilikuwa kurudia mwenyewe tena na tena na 1081 00:40:47,500 --> 00:40:50,930 namna fulani kutupa mbali, kutupa mbali, kutupa mbali, nusu ya tatizo, au 1082 00:40:50,930 --> 00:40:55,320 ujumla, kugawa tatizo katika nusu, na kisha kutibu kipande kidogo cha 1083 00:40:55,320 --> 00:40:59,630 tatizo kama conceptually sawa hadi mwingine, sisi kwa namna fulani alifanya 1084 00:40:59,630 --> 00:41:00,910 kimsingi bora. 1085 00:41:00,910 --> 00:41:04,720 Lakini pamoja na aina Bubble, na uteuzi aina, na aina ya kuingizwa, tumekuwa anaweza 1086 00:41:04,720 --> 00:41:06,560 hakuna utambuzi huo kwamba Jennifer alivyofanya. 1087 00:41:06,560 --> 00:41:10,220 Sisi pretty much tu kutembea nyuma na nje rundo zima la nyakati, na sisi 1088 00:41:10,220 --> 00:41:12,650 mambo tweaked kidogo, swapping katika utaratibu huu, labda 1089 00:41:12,650 --> 00:41:13,730 kuingiza au kuchagua. 1090 00:41:13,730 --> 00:41:16,950 Lakini mwisho wa siku, mimi alifanya mengi ya kutembea Awkward na kurudi. 1091 00:41:16,950 --> 00:41:21,160 Sisi si kweli kujiinua kitu smart kama Jennifer alifanya kama kugawa 1092 00:41:21,160 --> 00:41:22,040 na mshindi. 1093 00:41:22,040 --> 00:41:25,620 >> Hivyo kuunganisha aina, kwa kulinganisha, ambayo sisi hawaoni mpaka wiki ijayo, ni kwenda 1094 00:41:25,620 --> 00:41:29,540 kujiinua kwamba wazo muhimu kwa kugawa pembejeo, na kisha kupunguza nusu, na kisha 1095 00:41:29,540 --> 00:41:30,580 kupunguza nusu, na kisha kupunguza nusu. 1096 00:41:30,580 --> 00:41:34,590 Na juu ya kila iteration ya kitanzi kwamba, Uamuzi nusu ya kushoto, na haki ya 1097 00:41:34,590 --> 00:41:38,200 nusu, basi nusu ya kushoto ya nusu ya kushoto, na nusu wa kulia wa kushoto, basi 1098 00:41:38,200 --> 00:41:40,990 nusu ya kushoto ya nusu ya haki, na nusu ya haki ya nusu ya haki. 1099 00:41:40,990 --> 00:41:42,840 Na kurudia tena na tena. 1100 00:41:42,840 --> 00:41:46,170 >> Hivyo utaona hii kuibua, lakini hii ni nini watapata sisi wiki ijayo. 1101 00:41:46,170 --> 00:41:49,760 Na kwa ujumla, wakati sisi kufikiri kidogo vigumu kidogo juu ya tatizo lolote kama hayo. 1102 00:41:49,760 --> 00:41:52,435 1103 00:41:52,435 --> 00:41:57,970 Tuna n squared upande wa kushoto, n mraba katikati, na n 1104 00:41:57,970 --> 00:41:59,400 logi n juu ya haki. 1105 00:41:59,400 --> 00:42:00,590 Hivyo kuna cliffhanger yako halisi. 1106 00:42:00,590 --> 00:42:02,040 Tutaweza kuona juu ya Jumatatu. 1107 00:42:02,040 --> 00:42:05,163 >> [Makofi]