1 00:00:00,000 --> 00:00:03,440 >> [MUSIC KUCHEZA] 2 00:00:03,440 --> 00:01:57,217 3 00:01:57,217 --> 00:02:00,710 >> [Makofi] 4 00:02:00,710 --> 00:02:05,700 5 00:02:05,700 --> 00:02:09,669 >> DAVID J. Malan: Hii ni CS50, Chuo Kikuu cha Harvard kuanzishwa 6 00:02:09,669 --> 00:02:12,370 kwa akili makampuni ya biashara ya sayansi ya kompyuta 7 00:02:12,370 --> 00:02:14,180 na sanaa ya programu. 8 00:02:14,180 --> 00:02:17,530 Sasa kama wewe ni miongoni mwa wale kila mwaka ni kukaa hapa 9 00:02:17,530 --> 00:02:21,450 na kidogo ya mishipa katika akili yako, kama kwamba wewe sidhani wewe ni hapa, 10 00:02:21,450 --> 00:02:24,270 wewe unadhani kwamba wengi mtu yeyote kukaa karibu na wewe 11 00:02:24,270 --> 00:02:27,730 anajua mbali zaidi kuliko wewe, ni kweli vizuri zaidi kuliko wewe katika kompyuta 12 00:02:27,730 --> 00:02:30,430 sayansi au kompyuta kwa ujumla zaidi, kutambua 13 00:02:30,430 --> 00:02:36,140 kwamba 78% ya wanafunzi ambao sasa kuchukua CS50 hawana uzoefu kabla. 14 00:02:36,140 --> 00:02:39,570 >> Hakika, kuna dots 100 huko juu ya kuonyesha, 78 ya ambayo 15 00:02:39,570 --> 00:02:43,540 ni kijani imara, ambayo ina maana, kama wewe ni kati ya kwamba idadi ya watu, 16 00:02:43,540 --> 00:02:46,420 ni katika kampuni nzuri sana hapa juu ya nje. 17 00:02:46,420 --> 00:02:50,320 Na kama wewe ni badala kati ya 22% ya CS50 wanafunzi ambao kufanya kweli 18 00:02:50,320 --> 00:02:53,920 kuwa na uzoefu kabla, kama katika shule ya sekondari au baadhi ya programu nyingine, 19 00:02:53,920 --> 00:02:56,430 kutambua kuwa wewe, pia, kuwa changamoto katika shaka. 20 00:02:56,430 --> 00:02:59,930 >> Si tu kufanya sisi kuwa na nyimbo tofauti kwa ajili ya wanafunzi chini ya starehe na zaidi 21 00:02:59,930 --> 00:03:03,789 starehe sawa katika sehemu, sisi pia kuwa kinachojulikana hacker matoleo 22 00:03:03,789 --> 00:03:06,080 ya wengi tatizo seti kwamba changamoto wanafunzi hao 23 00:03:06,080 --> 00:03:09,650 na uzoefu kwamba ziada kuchunguza vifaa sawa 24 00:03:09,650 --> 00:03:12,140 lakini kutoka zaidi kisasa mtazamo. 25 00:03:12,140 --> 00:03:13,900 >> Lakini sayansi ya kompyuta ni nini? 26 00:03:13,900 --> 00:03:17,750 Naam, hatimaye, nini kinaendelea jambo kama wewe kuchunguza uwanja huu ni si 27 00:03:17,750 --> 00:03:20,500 sana ambapo wewe kuishia jamaa na wanafunzi wako, 28 00:03:20,500 --> 00:03:25,350 lakini ambapo wewe mwenyewe kuishia katika wiki 12 dhidi ya ambapo wewe kuanza hapa 29 00:03:25,350 --> 00:03:26,720 katika wiki sifuri. 30 00:03:26,720 --> 00:03:31,850 Sasa kompyuta science-- vizuri, hebu kuiita sayansi ya computation-- 31 00:03:31,850 --> 00:03:35,910 ambapo computation ni kweli tu dhana njia ya kusema, kuchukua baadhi ya pembejeo, 32 00:03:35,910 --> 00:03:39,460 kuzalisha baadhi pato, na kufanya hivyo kwa kuendesha algorithms, 33 00:03:39,460 --> 00:03:43,700 seti ya maelekezo kwa ajili ya kutatua baadhi ya tatizo juu ya pembejeo wale 34 00:03:43,700 --> 00:03:48,460 ili kuzalisha baadhi ya pato au ufumbuzi katika ambayo una nia. 35 00:03:48,460 --> 00:03:51,310 >> Hivyo sisi hivi karibuni alikuwa nafasi ya kusafiri nje 36 00:03:51,310 --> 00:03:53,170 California kwa kukutana na alumna. 37 00:03:53,170 --> 00:03:54,650 Jina lake ni Susan Wojcicki. 38 00:03:54,650 --> 00:03:57,190 Na yeye Ningependa kusema na wewe hapa juu ya video 39 00:03:57,190 --> 00:04:01,690 kushuhudia kwa jinsi husika hata tu ladha ya kompyuta 40 00:04:01,690 --> 00:04:03,770 sayansi katika ngazi ya utangulizi wanaweza kuwa. 41 00:04:03,770 --> 00:04:06,870 Hata kama huna kwenda juu ya kujiingiza sayansi ya kompyuta kama shamba, 42 00:04:06,870 --> 00:04:09,330 au hata uhandisi, au STEM kwa ujumla zaidi, 43 00:04:09,330 --> 00:04:12,360 utaona, kwa kweli, jinsi baadhi ya Bila shaka hivyo kusukumwa maisha yake. 44 00:04:12,360 --> 00:04:16,630 Na yeye tu tu alichukua wakati yeye mara mwandamizi hapa katika Harvard College. 45 00:04:16,630 --> 00:04:19,482 >> Kama tunaweza dim taa kwa Susan. 46 00:04:19,482 --> 00:04:20,690 Susan Wojcicki: Hello, ulimwengu. 47 00:04:20,690 --> 00:04:22,100 Mimi nina Susan Wojcicki. 48 00:04:22,100 --> 00:04:24,110 Mimi nina Mkurugenzi Mtendaji wa YouTube. 49 00:04:24,110 --> 00:04:29,150 Na mimi alichukua CS50 wakati mimi nilikuwa mwandamizi katika Harvard katika 1990. 50 00:04:29,150 --> 00:04:31,220 Mimi kwa kweli historia na kubwa maandiko. 51 00:04:31,220 --> 00:04:36,760 >> Na majira yangu junior, Nikagundua kuwa labda mimi 52 00:04:36,760 --> 00:04:39,060 alitaka kujifunza kitu kuhusu kompyuta. 53 00:04:39,060 --> 00:04:40,930 Na hivyo, mimi akaja nyuma. 54 00:04:40,930 --> 00:04:42,500 Mimi alichukua CS50. 55 00:04:42,500 --> 00:04:46,940 Ilikuwa vigumu, lakini ilikuwa ni darasa kushangaza zaidi mimi alichukua. 56 00:04:46,940 --> 00:04:49,630 >> Ni iliyopita jinsi mimi kufikiri juu ya kila kitu. 57 00:04:49,630 --> 00:04:55,810 Na wakati mimi wamemaliza Harvard mwaka 1990, nilikwenda Silicon Valley. 58 00:04:55,810 --> 00:04:57,140 Na mimi got kazi. 59 00:04:57,140 --> 00:05:00,150 Na mimi tumekuwa kufanya kazi katika tech tangu wakati huo. 60 00:05:00,150 --> 00:05:02,650 DAVID J. Malan: Sasa nini Susan hakutaja katika video hii, 61 00:05:02,650 --> 00:05:05,340 kuwa ni kweli katika yake karakana ambayo Google yenyewe ilikuwa 62 00:05:05,340 --> 00:05:07,420 ilianzishwa na Larry na Sergey. 63 00:05:07,420 --> 00:05:11,169 >> Sasa sisi pia kufikiwa nje kwa marafiki zetu katika code.org, shirika 64 00:05:11,169 --> 00:05:13,460 zaidi ya mwaka uliopita imekuwa kupata watu hasa 65 00:05:13,460 --> 00:05:16,520 msisimko juu ya sayansi ya kompyuta na programu, hasa. 66 00:05:16,520 --> 00:05:20,590 Lakini ni thamani akibainisha programu kwamba ni si sayansi ya kompyuta per se. 67 00:05:20,590 --> 00:05:22,090 Sayansi ya kompyuta ni si programu. 68 00:05:22,090 --> 00:05:24,560 Badala yake programu ni tu tool-- ambayo nyote 69 00:05:24,560 --> 00:05:27,510 itakuwa yote vizuri mno familiar na end-- muhula ya 70 00:05:27,510 --> 00:05:30,650 kama kwamba unaweza kuomba si tu kwa kozi ya baadaye katika CS 71 00:05:30,650 --> 00:05:33,670 lakini kwa mashamba chochote kutoka huko wewe ni ijayo, katika masomo ya sanaa, 72 00:05:33,670 --> 00:05:36,090 sayansi ya jamii, asili sayansi, au kama. 73 00:05:36,090 --> 00:05:39,740 >> Hakika, kuruhusu wengine wachache Mbegu na wenzao 74 00:05:39,740 --> 00:05:43,400 kuzungumza na applicability ya shamba kwamba watapata. 75 00:05:43,400 --> 00:05:52,340 76 00:05:52,340 --> 00:05:57,350 >> BILL GATES: Mimi nilikuwa 13 wakati mimi kwanza got upatikanaji wa kompyuta. 77 00:05:57,350 --> 00:06:00,485 >> JACK DORSEY: Wazazi wangu kununuliwa mimi Macintosh mwaka 1984 78 00:06:00,485 --> 00:06:01,640 wakati mimi nilikuwa miaka nane-ya zamani. 79 00:06:01,640 --> 00:06:02,990 >> Mark Zuckerberg: Mimi nilikuwa katika darasa la sita. 80 00:06:02,990 --> 00:06:04,670 >> SPIKA 1: Mimi kujifunza kwa kificho katika chuo. 81 00:06:04,670 --> 00:06:09,080 >> Ruchi SANGHVI: Freshman mwaka, kwanza muhula, Intro kwa Sayansi ya Kompyuta. 82 00:06:09,080 --> 00:06:11,850 >> BILL GATES: I aliandika mpango kwamba alicheza tic-tac-toe. 83 00:06:11,850 --> 00:06:14,100 >> DREW HOUSTON: Nadhani ilikuwa ni pretty mnyenyekevu mwanzo. 84 00:06:14,100 --> 00:06:16,370 Nadhani mpango wa kwanza Niliandika aliuliza mambo kama, 85 00:06:16,370 --> 00:06:17,820 nini rangi yako favorite? 86 00:06:17,820 --> 00:06:18,696 Au jinsi ya zamani ni wewe? 87 00:06:18,696 --> 00:06:21,070 ELENA SILENOK: mimi kwanza kujifunza jinsi ya kufanya mduara kijani 88 00:06:21,070 --> 00:06:23,670 na mraba nyekundu kuonekana kwenye screen. 89 00:06:23,670 --> 00:06:25,420 GABE NEWELL: wa kwanza wakati mimi kwa kweli alikuwa na 90 00:06:25,420 --> 00:06:27,360 kitu kuja juu na kusema, hello, dunia. 91 00:06:27,360 --> 00:06:29,710 Na mimi alifanya kompyuta kufanya hivyo. 92 00:06:29,710 --> 00:06:30,850 Ni mara tu ya kushangaza. 93 00:06:30,850 --> 00:06:33,224 >> Mark Zuckerberg: Kujifunza jinsi kwa mpango hakuwa na kuanza off 94 00:06:33,224 --> 00:06:35,450 kama kutaka kujifunza yote ya sayansi ya kompyuta 95 00:06:35,450 --> 00:06:38,630 au kujaribu bwana hii nidhamu au kitu kama hicho. 96 00:06:38,630 --> 00:06:41,591 Ni tu ya kuanza mbali kwa sababu mimi alitaka kufanya jambo hili moja rahisi. 97 00:06:41,591 --> 00:06:44,340 Nilitaka kufanya kitu ambacho Ilikuwa ni furaha kwa ajili yangu mwenyewe na dada zangu. 98 00:06:44,340 --> 00:06:46,399 >> Na mimi aliandika mpango huu kidogo. 99 00:06:46,399 --> 00:06:48,440 Na kisha kimsingi tu aliongeza kidogo yake. 100 00:06:48,440 --> 00:06:49,930 Na kisha wakati mimi zinahitajika kujifunza kitu kipya, 101 00:06:49,930 --> 00:06:52,210 Nikaona it up, ama katika kitabu au juu ya internet, 102 00:06:52,210 --> 00:06:53,240 na kisha aliongeza kidogo yake. 103 00:06:53,240 --> 00:06:56,300 >> DREW HOUSTON: Ni kweli si tofauti na kucheza chombo au kitu 104 00:06:56,300 --> 00:07:00,007 au kucheza mchezo. 105 00:07:00,007 --> 00:07:01,090 DAVID J. Malan: All wa kulia. 106 00:07:01,090 --> 00:07:04,120 Kwa hiyo, acheni sasa kweli kupiga mbizi katika undani kidogo. 107 00:07:04,120 --> 00:07:07,430 Ni pembejeo hizi na matokeo gani kwamba sisi ni kuzungumza juu ya hapa? 108 00:07:07,430 --> 00:07:09,110 >> Basi vipi kuhusu kitu rahisi? 109 00:07:09,110 --> 00:07:12,120 Pengine kujua, hata kama una hakuna uzoefu na sayansi ya kompyuta 110 00:07:12,120 --> 00:07:16,570 chochote, kwamba kompyuta kwa namna fulani kutumia na anaelewa zeros na ndio tu. 111 00:07:16,570 --> 00:07:20,500 Lakini jinsi gani kwamba uwezekano kuwa kutokana na jinsi desktops sana leo na Laptops sawa 112 00:07:20,500 --> 00:07:21,280 unaweza kufanya? 113 00:07:21,280 --> 00:07:24,310 >> DNA wa siku, tu alfabeti ya kwamba wao kuelewa 114 00:07:24,310 --> 00:07:26,410 ni zero au moja. 115 00:07:26,410 --> 00:07:27,470 Naam, kufikiria hili. 116 00:07:27,470 --> 00:07:30,840 Sisi, binadamu, huwa na kutumia mfumo wa decimal. "Desemba" maana 10. 117 00:07:30,840 --> 00:07:33,970 Na kwamba ni 10 kwa sababu tuna Tarakimu 10, 0 kupitia tisa. 118 00:07:33,970 --> 00:07:36,180 >> Sasa kompyuta, kwa upande wake, huwa na kutumia binary. 119 00:07:36,180 --> 00:07:37,270 "Bi" maana mbili. 120 00:07:37,270 --> 00:07:39,560 Hivyo wao huwa na kutumia zero tu na mmoja. 121 00:07:39,560 --> 00:07:42,680 Lakini ni zamu nje, kwamba hata tu na zeros na ndio, kwamba 122 00:07:42,680 --> 00:07:45,900 ni alfabeti kubwa ya kutosha na ambayo kwa kuwakilisha zaidi 123 00:07:45,900 --> 00:07:48,490 kipande yoyote ya data unataka, kama ni ya simu, 124 00:07:48,490 --> 00:07:52,100 kama ni barua, kama ni graphic au video kwenye screen. 125 00:07:52,100 --> 00:07:57,140 >> Fikiria, kwa mfano, jinsi sisi binadamu kawaida kutafsiri idadi hii hapa. 126 00:07:57,140 --> 00:08:00,010 Hii ni tatu tu tarakimu, moja, mbili, tatu. 127 00:08:00,010 --> 00:08:04,570 Lakini tunajua idadi hii innately sasa kama 123. 128 00:08:04,570 --> 00:08:05,510 Lakini kwa nini ni kwamba? 129 00:08:05,510 --> 00:08:07,570 >> Naam, kama unafikiri nyuma labda shule ya daraja, 130 00:08:07,570 --> 00:08:11,700 pengine walikuwa kufundishwa kufikiri ya namba hizi kama kuwa katika nguzo, 131 00:08:11,700 --> 00:08:14,700 ambapo moja ni katika mamia mahali, wawili ni katika mamia mahali, 132 00:08:14,700 --> 00:08:16,360 na tatu ni katika wale mahali. 133 00:08:16,360 --> 00:08:17,790 Kwa nini ni kwamba kweli muhimu? 134 00:08:17,790 --> 00:08:19,665 Naam, kufikiri juu ya hesabu super rahisi 135 00:08:19,665 --> 00:08:22,219 kwamba sisi wote wamekuwa kufanya kwa miaka sasa. 136 00:08:22,219 --> 00:08:24,510 Ufanisi, kama nimepata moja katika mamia mahali, 137 00:08:24,510 --> 00:08:29,610 kufanya math haraka 100 mara 1 plus 10 mara 2-- 138 00:08:29,610 --> 00:08:33,059 kwa sababu mbili ni katika mamia place-- plus 1 mara 3-- 139 00:08:33,059 --> 00:08:34,830 kwa sababu tatu ni katika wale mahali. 140 00:08:34,830 --> 00:08:37,039 Hivyo, bila shaka, kama sisi kweli kuzidisha hii nje, 141 00:08:37,039 --> 00:08:39,600 nini sisi ni kweli anayewakilisha na hii moja pattern-- 142 00:08:39,600 --> 00:08:46,150 mbili three-- ni 100 pamoja na 20 pamoja na 3, ambayo, bila shaka, ni 123. 143 00:08:46,150 --> 00:08:51,130 >> Sasa binary, na kompyuta kwa kweli, kimsingi kuzungumza lugha moja 144 00:08:51,130 --> 00:08:51,680 kwamba sisi kufanya. 145 00:08:51,680 --> 00:08:53,400 Wao tu alfabeti ndogo. 146 00:08:53,400 --> 00:08:57,100 Hivyo kompyuta tu na zeros na wale ovyo yao. 147 00:08:57,100 --> 00:09:02,500 Hivyo ambapo sisi binadamu kuwa kimsingi mamlaka ya 10 katika kila moja ya haya places-- 148 00:09:02,500 --> 00:09:06,810 10 hadi sifuri, 10 kwa moja, kumi kwa mbili, kutoa 110 na 100 149 00:09:06,810 --> 00:09:07,700 mtiririko huo. 150 00:09:07,700 --> 00:09:12,140 >> Kwa sababu kompyuta tu kuwa na maadili mbili wanaweza kuelewa, sifuri na moja, 151 00:09:12,140 --> 00:09:16,600 wao kutumia viwango tofauti katika nguzo hizi, moja, mbili, nne. 152 00:09:16,600 --> 00:09:20,480 Na kama sisi naendelea kwenda, nane, 16, 32, 64, na kadhalika. 153 00:09:20,480 --> 00:09:24,220 Lakini muundo na mawazo yao ni sawa. 154 00:09:24,220 --> 00:09:27,340 >> Hivyo kwa mantiki hii, mtu yeyote, jinsi gani Mimi kwenda kuhusu anayewakilisha idadi 155 00:09:27,340 --> 00:09:28,530 moja katika binary? 156 00:09:28,530 --> 00:09:33,080 Kama wewe sijawahi hata mawazo kuhusu hii kabla, nini gut yako kusema? 157 00:09:33,080 --> 00:09:33,777 >> Watazamaji: One. 158 00:09:33,777 --> 00:09:34,610 DAVID J. Malan: One. 159 00:09:34,610 --> 00:09:35,660 Hasa. 160 00:09:35,660 --> 00:09:38,100 Sisi tu haja ya moja katika mahali ndio sababu zeros 161 00:09:38,100 --> 00:09:40,610 inatosha kutupa wala nne wala mbili. 162 00:09:40,610 --> 00:09:42,440 Hivyo mara moja moja sawa na moja. 163 00:09:42,440 --> 00:09:43,940 Sasa, mambo kupata kidogo ya kuvutia. 164 00:09:43,940 --> 00:09:46,830 Kama mimi nataka kuwakilisha katika binary idadi two-- lakini, 165 00:09:46,830 --> 00:09:49,790 tena, hata kama wewe sijawahi amesema lugha hii kabla, 166 00:09:49,790 --> 00:09:54,680 jinsi ya kufanya sisi kuwakilisha katika binary thamani sisi binadamu kujua kama mbili? 167 00:09:54,680 --> 00:09:55,570 Zero moja sifuri. 168 00:09:55,570 --> 00:09:57,620 Tu ya kuweka moja katika safu kwamba unataka. 169 00:09:57,620 --> 00:09:59,560 >> Sasa ni kupata pretty rahisi pengine sasa. 170 00:09:59,560 --> 00:10:02,950 Hivyo kama nataka kuwakilisha three-- kuna safu hakuna tatu ya. 171 00:10:02,950 --> 00:10:06,770 Hivyo, tena, siwezi sasa kuongeza maadili haya pamoja na kuweka moja hapa. 172 00:10:06,770 --> 00:10:10,320 Hivyo 2 mara 1 plus 1 mara 1 ni, bila shaka, 3. 173 00:10:10,320 --> 00:10:13,480 >> Sasa, mambo kupata furaha kidogo katika kwamba ndio sasa kuwa zeros. 174 00:10:13,480 --> 00:10:15,480 Na kuwakilisha nne, mimi kupata hii. 175 00:10:15,480 --> 00:10:19,310 Na kama sisi nyongeza polepole here-- kwamba itakuwa tano. 176 00:10:19,310 --> 00:10:20,700 Hii itakuwa sita. 177 00:10:20,700 --> 00:10:22,100 Hii itakuwa saba. 178 00:10:22,100 --> 00:10:25,310 >> Lakini sasa mimi wanaonekana kuwa na kukimbia katika tatizo. 179 00:10:25,310 --> 00:10:30,520 Jinsi gani mimi kwenda kuhusu anayewakilisha eight-- itakuwa thamani ijayo. 180 00:10:30,520 --> 00:10:31,900 Yeah, hivyo tunahitaji bits mpya. 181 00:10:31,900 --> 00:10:33,899 Na, kwa hakika, kama wameweza habari msemo huu kabla, 182 00:10:33,899 --> 00:10:37,380 bits, hiyo ni muda mfupi tu kwa binary tarakimu, zero au moja. 183 00:10:37,380 --> 00:10:41,520 >> Na hivyo mimi kutokea kwa kuwa anayewakilisha tu tatu bits kama hapa. 184 00:10:41,520 --> 00:10:44,900 Lakini kama mimi alikuwa na njia ya kuhifadhi si tatu bits mbalimbali, lakini nne, 185 00:10:44,900 --> 00:10:47,250 Hakika mimi naweza kuwakilisha nane, tisa na kisha, na kisha 186 00:10:47,250 --> 00:10:49,400 10, na hata ya juu na ya juu. 187 00:10:49,400 --> 00:10:52,140 >> Lakini hiyo kisha wito ndani ya swali jinsi gani tunaweza 188 00:10:52,140 --> 00:10:54,540 kwenda juu anayewakilisha haya mambo katika nafasi ya kwanza. 189 00:10:54,540 --> 00:10:56,950 Ni jambo moja kwa kuteka yao juu hapa juu ya slide, 190 00:10:56,950 --> 00:11:00,660 lakini ni jinsi gani unaweza kuwawakilisha kama wewe ni kifaa mitambo? 191 00:11:00,660 --> 00:11:04,390 Je, ni kompyuta kufanya kwa kuwakilisha pembejeo na mazao kwamba 192 00:11:04,390 --> 00:11:09,020 kimsingi kufafanua computation mwisho wa siku? 193 00:11:09,020 --> 00:11:12,090 >> Naam, nini kuhusu kitu super rahisi kama hii? 194 00:11:12,090 --> 00:11:13,200 Ni tu balbu ya mwanga. 195 00:11:13,200 --> 00:11:15,460 Na mimi inaweza kusababisha hii mwanga bulb kwenda juu ya 196 00:11:15,460 --> 00:11:17,920 na kugeuka baadhi umeme juu ya na kuruhusu elektroni 197 00:11:17,920 --> 00:11:22,585 kati yake kwa njia, ambayo mabadiliko ya yake hali au thamani yake, hivyo kusema. 198 00:11:22,585 --> 00:11:24,460 Kwa mfano, hii ni umri wa shule ya dawati taa 199 00:11:24,460 --> 00:11:27,250 hapa na moja kama mwanga bulb ndani yake. 200 00:11:27,250 --> 00:11:29,940 Na sasa hivi ni si kweli kufanya kitu chochote muhimu. 201 00:11:29,940 --> 00:11:32,680 Lakini kwa haraka kama mimi kuziba ndani ya tundu umeme 202 00:11:32,680 --> 00:11:36,390 na kisha kutumia switch-- hii au tunaweza hata simu yake transistor 203 00:11:36,390 --> 00:11:39,970 au kufikiria kama such-- Mimi sasa wanaweza kuwakilisha ama 204 00:11:39,970 --> 00:11:44,120 thamani hii, ambapo bulb mwanga ya wazi mbali, au thamani hii. 205 00:11:44,120 --> 00:11:46,060 Thamani hii au thamani hii. 206 00:11:46,060 --> 00:11:47,520 Thamani hii na kadhalika. 207 00:11:47,520 --> 00:11:51,220 >> Hivyo ndani ya kompyuta, labda, ni vipande ndogo sana ya vifaa, 208 00:11:51,220 --> 00:11:52,970 lakini kwamba mwishoni ya siku tu na 209 00:11:52,970 --> 00:11:55,360 kutumia electricity-- labda kukamata it-- 210 00:11:55,360 --> 00:11:59,730 na basi ama kuweka kitu juu ya au kuweka kitu mbali. 211 00:11:59,730 --> 00:12:02,021 Bila shaka, hii ni si hasa ya kuvutia ya kufanya 212 00:12:02,021 --> 00:12:03,270 na moja tu mwanga bulb. 213 00:12:03,270 --> 00:12:06,726 >> Kwa kweli, jinsi ya juu naweza kuhesabu katika binary na hii taa dawati hapa? 214 00:12:06,726 --> 00:12:07,420 >> Watazamaji: One. 215 00:12:07,420 --> 00:12:08,545 >> DAVID J. Malan: One, haki? 216 00:12:08,545 --> 00:12:11,020 Mimi haja zaidi dawati taa kama mimi kweli wanataka kuhesabu juu. 217 00:12:11,020 --> 00:12:12,210 Lakini tunaweza kufanya vizuri zaidi kuliko hiyo. 218 00:12:12,210 --> 00:12:14,460 Kwa sababu balbu mwanga kwamba tumekuwa kuweka katika mambo haya 219 00:12:14,460 --> 00:12:17,730 ni kweli fancier balbu mwanga kuliko yesteryear itaruhusu. 220 00:12:17,730 --> 00:12:20,310 Na wao uko kweli mtandao balbu mwanga. 221 00:12:20,310 --> 00:12:23,160 Na mashada ya makampuni kufanya mambo haya siku hizi. 222 00:12:23,160 --> 00:12:25,190 >> Lakini zinageuka kuwa hii moja hasa 223 00:12:25,190 --> 00:12:27,680 kuja na kipengele ambapo unaweza kubadilisha rangi yake. 224 00:12:27,680 --> 00:12:30,810 Hivyo kwa mfano, kama wewe kupambwa Dorm chumba yako 225 00:12:30,810 --> 00:12:33,200 na wachache wa haya mwanga balbu, kulingana na hisia zako, 226 00:12:33,200 --> 00:12:35,366 kutegemea ambaye huja katika, kutegemea hali ya hewa, 227 00:12:35,366 --> 00:12:37,360 kutegemea na wakati wa siku, unaweza kweli 228 00:12:37,360 --> 00:12:40,300 mabadiliko ya rangi ya balbu katika chumba yako. 229 00:12:40,300 --> 00:12:43,740 Na kwamba ni kwa sababu hizi mwanga balbu na wengine kama hayo na nini 230 00:12:43,740 --> 00:12:48,010 kuitwa API, maombi programu interface, ambayo 231 00:12:48,010 --> 00:12:50,920 ni mada ambayo wewe utakuwa vizuri ukoo na na mwisho wa muhula ya. 232 00:12:50,920 --> 00:12:53,710 >> Na hii ni dhana tu, njia cryptic ya kusema, 233 00:12:53,710 --> 00:12:57,570 unaweza mpango haya mwanga balbu kwa kufanya amri yako. 234 00:12:57,570 --> 00:13:00,360 Unaweza kutuma ujumbe yao kama wewe, binadamu, 235 00:13:00,360 --> 00:13:03,640 unaweza kutuma ujumbe kwa mtandao wa kompyuta akisema, nipe habari leo 236 00:13:03,640 --> 00:13:05,110 au nipe email yangu. 237 00:13:05,110 --> 00:13:08,010 >> Unaweza kutuma zaidi arcane ujumbe kwa balbu mwanga hizi 238 00:13:08,010 --> 00:13:09,700 kusema, kurejea kwenye na kugeuka mbali. 239 00:13:09,700 --> 00:13:11,370 Lakini si kwamba wote kwamba kuvutia. 240 00:13:11,370 --> 00:13:14,280 Unaweza kusema, kurejea kwenye nyekundu, kurejea kwenye kijani, kurejea kwenye bluu, 241 00:13:14,280 --> 00:13:15,990 wote kwa mwanga huo bulb. 242 00:13:15,990 --> 00:13:20,990 Na unaweza hata, na kidogo zaidi savvy, kusema, kugeuka mwenyewe na bluu 243 00:13:20,990 --> 00:13:24,710 wakati ni siku gloomy nje, kwa mfano. 244 00:13:24,710 --> 00:13:27,910 Ni kweli unaweza kiraka katika hali ya hewa API na kujua 245 00:13:27,910 --> 00:13:32,260 nini hali ya hewa ni, au wakati wa siku, au nyingine kuchochea hiyo. 246 00:13:32,260 --> 00:13:35,550 >> Hiyo, kwa kweli, wawili kati ya Wanachama CS50 ya mwenyewe wafanyakazi, 247 00:13:35,550 --> 00:13:38,827 Dan Bradley na Ansel Duff hapa, kindly zilizonunuliwa 248 00:13:38,827 --> 00:13:40,410 sisi rundo zima la balbu hizi mwanga. 249 00:13:40,410 --> 00:13:42,910 Na wao kujengwa CS50 ya kwanza balbu milele binary, 250 00:13:42,910 --> 00:13:46,850 ambapo tumekuwa kuwakilishwa here-- na haya playful magnets-- kidogo 251 00:13:46,850 --> 00:13:49,780 placeholders mbalimbali sisi alluded kidogo tu iliyopita. 252 00:13:49,780 --> 00:13:52,572 >> Hivyo njia juu ya hapa ni mahali ndio, mbili, nne. 253 00:13:52,572 --> 00:13:54,030 Na sisi hawakuona juu zaidi kuliko ile. 254 00:13:54,030 --> 00:13:55,613 Lakini, bila shaka, wao ni mamlaka ya mbili. 255 00:13:55,613 --> 00:13:59,490 Nane, 16, 32, 64, na 128. 256 00:13:59,490 --> 00:14:03,320 Hivyo kama mimi sasa wanataka kuwa kidogo fancier kuliko kutumia hii kubadili umri wa shule ya, 257 00:14:03,320 --> 00:14:07,310 Nina hapa juu ya iPad hii interface rahisi super 258 00:14:07,310 --> 00:14:10,440 kwamba Dan Bradley, aliyekuwa mwanafunzi na sasa kufundisha wenzake, 259 00:14:10,440 --> 00:14:13,510 programed kwa kutumia baadhi ya HTML na JavaScript, ambayo 260 00:14:13,510 --> 00:14:15,685 ni ghafi na programu lugha kwa mtiririko huo. 261 00:14:15,685 --> 00:14:17,560 Na pengine unaweza see-- hata katika back-- 262 00:14:17,560 --> 00:14:21,670 kuna plus kubwa na minus kubwa, pamoja na kifungo moja kwa kila moja ya balbu hizi. 263 00:14:21,670 --> 00:14:25,740 Na nini hii ni kwenda naomba je ni, kwa mfano, bonyeza plus 264 00:14:25,740 --> 00:14:28,250 na sasa kuwakilisha, ya Bila shaka, nini idadi? 265 00:14:28,250 --> 00:14:28,750 One. 266 00:14:28,750 --> 00:14:30,220 Na siwezi hit tena. 267 00:14:30,220 --> 00:14:31,480 Mbili. 268 00:14:31,480 --> 00:14:32,800 Tatu. 269 00:14:32,800 --> 00:14:33,950 Nne. 270 00:14:33,950 --> 00:14:35,200 Tano. 271 00:14:35,200 --> 00:14:36,360 Sita. 272 00:14:36,360 --> 00:14:36,880 Saba. 273 00:14:36,880 --> 00:14:40,740 >> Na hapa sasa sisi kupata kwamba rollover, lakini tuna nne kidogo wakati huu, 274 00:14:40,740 --> 00:14:42,180 hivyo sasa tuna nane. 275 00:14:42,180 --> 00:14:44,000 Hivyo tunaweza kufanya hii kwa muda kabisa. 276 00:14:44,000 --> 00:14:46,530 Kwa kweli, kama kando, jinsi ya juu tunaweza kuhesabu? 277 00:14:46,530 --> 00:14:48,318 Mtu yeyote? 278 00:14:48,318 --> 00:14:49,270 >> Watazamaji: 255. 279 00:14:49,270 --> 00:14:51,420 >> DAVID J. Malan: 255, sawa? 280 00:14:51,420 --> 00:14:54,900 Je, si wasiwasi sana juu ya math kwa sasa, lakini hiyo ni idadi pretty heshima. 281 00:14:54,900 --> 00:14:59,140 Lakini ni kweli haina amefungwa tu vipande wangapi wa habari, 282 00:14:59,140 --> 00:15:01,760 kama barua, au graphic kwamba tunaweza kuwakilisha. 283 00:15:01,760 --> 00:15:02,697 >> Lakini hakuna jambo kwa sasa. 284 00:15:02,697 --> 00:15:04,530 Mimi nina kwenda mbele na kurejea kwao yote mbali. 285 00:15:04,530 --> 00:15:09,670 Na kama mimi naweza, Ningependa kuuliza kwa kujitolea, volunteer-- yetu ya kwanza 286 00:15:09,670 --> 00:15:11,342 oh, hello-- juu ya hatua. 287 00:15:11,342 --> 00:15:14,050 catch ni wewe kuwa starehe ya kuonekana, kama wewe wazi 288 00:15:14,050 --> 00:15:17,421 ni mbele ya wanafunzi wako wote, kama vile juu ya internet. 289 00:15:17,421 --> 00:15:20,420 Na napenda kuangalia kidogo zaidi ya the-- vipi kuhusu hapa katika shati nyeupe? 290 00:15:20,420 --> 00:15:20,920 Na mkono up. 291 00:15:20,920 --> 00:15:22,071 Kuja juu juu. 292 00:15:22,071 --> 00:15:22,820 Jina lako ni nani? 293 00:15:22,820 --> 00:15:23,760 >> Watazamaji: Jackie. 294 00:15:23,760 --> 00:15:24,718 >> DAVID J. Malan: Jackie. 295 00:15:24,718 --> 00:15:25,820 Jackie, kuja juu up. 296 00:15:25,820 --> 00:15:29,820 Basi nini kuna pia juu ya hili iPad ni kifungo kuitwa Game Mode. 297 00:15:29,820 --> 00:15:32,570 Na Mode hii Game ni kwenda naomba pembejeo 298 00:15:32,570 --> 00:15:35,780 mapema decimal hasa simu, namba sisi binadamu ni 299 00:15:35,780 --> 00:15:36,760 familiar with. 300 00:15:36,760 --> 00:15:39,820 Na kisha itakuwa changamoto hapa kwa kutumia kifungo 301 00:15:39,820 --> 00:15:42,140 juu ya moja kwa top-- kila moja ya haya bulbs-- 302 00:15:42,140 --> 00:15:45,050 kwa kweli kufikiri muundo wa balbu mwanga 303 00:15:45,050 --> 00:15:46,970 kwamba inawakilisha idadi katika swali. 304 00:15:46,970 --> 00:15:47,790 >> Na mimi nina sorry, nini ilikuwa jina yako tena? 305 00:15:47,790 --> 00:15:48,250 >> Watazamaji: Jackie. 306 00:15:48,250 --> 00:15:48,620 >> DAVID J. Malan: Jackie. 307 00:15:48,620 --> 00:15:48,920 Wote haki. 308 00:15:48,920 --> 00:15:49,740 Nzuri ya kukutana na wewe. 309 00:15:49,740 --> 00:15:54,580 >> Hivyo basi mimi kwenda mbele na mpango katika kwa dunia ya kuona namba 15. 310 00:15:54,580 --> 00:15:56,360 Tutaweza kuweka ni ndogo mara ya kwanza hapa. 311 00:15:56,360 --> 00:15:58,240 Na mimi nina kwenda katika Game Mode. 312 00:15:58,240 --> 00:16:01,160 Na mimi nina kwenda bayana, kutupa namba 15. 313 00:16:01,160 --> 00:16:01,900 >> OK. 314 00:16:01,900 --> 00:16:05,510 Na sasa na kila mtu watching-- kama unataka labda kusimama njia hii, 315 00:16:05,510 --> 00:16:09,970 kwa sababu itakuwa line up-- kwenda mbele na kugeuza kifungo nane pamoja juu 316 00:16:09,970 --> 00:16:12,530 kugeuka juu ya balbu au mbali kama unaweza kuona inafaa. 317 00:16:12,530 --> 00:16:13,530 >> Watazamaji: OK. 318 00:16:13,530 --> 00:16:17,720 >> DAVID J. Malan: Na hakuna cheating kwa kupiga pamoja na mara 15. 319 00:16:17,720 --> 00:16:19,275 Oh, sisi ni kwenda kufanya hivyo. 320 00:16:19,275 --> 00:16:20,069 >> Watazamaji: Oh, kusubiri. 321 00:16:20,069 --> 00:16:20,610 Mimi hivyo sorry. 322 00:16:20,610 --> 00:16:22,660 >> DAVID J. Malan: Unaweza pia kurejea balbu mwanga juu ya mtu mmoja mmoja 323 00:16:22,660 --> 00:16:24,076 na kila moja ya hizi vifungo juu. 324 00:16:24,076 --> 00:16:24,844 Watazamaji: Oh, OK. 325 00:16:24,844 --> 00:16:27,429 Hivyo itakuwa like-- 326 00:16:27,429 --> 00:16:28,220 DAVID J. Malan: OK. 327 00:16:28,220 --> 00:16:29,100 Hivyo basi, tuna nane. 328 00:16:29,100 --> 00:16:31,280 Basi hebu pause kwa watazamaji kushiriki hapa. 329 00:16:31,280 --> 00:16:34,300 Nini idadi ni Jackie sasa anayewakilisha? 330 00:16:34,300 --> 00:16:34,800 11. 331 00:16:34,800 --> 00:16:35,730 Hivyo sisi ni karibu na hapo. 332 00:16:35,730 --> 00:16:38,360 333 00:16:38,360 --> 00:16:39,630 Na bora. 334 00:16:39,630 --> 00:16:41,487 Hivyo tuna mshindi wetu wa kwanza. 335 00:16:41,487 --> 00:16:42,445 Hongera. 336 00:16:42,445 --> 00:16:48,200 >> Na sisi mawazo tunatarajia kuwa na baadhi fabulous giveaways. 337 00:16:48,200 --> 00:16:50,860 Kama Ningependa kuwa mmoja kama Dorm chumba hapa juu ya chuo, 338 00:16:50,860 --> 00:16:56,126 unaweza wewe mwenyewe na mradi wa mwisho kutumia sasa API hii, shukrani kwa Jackie. 339 00:16:56,126 --> 00:16:57,050 Hivyo now-- 340 00:16:57,050 --> 00:16:58,902 >> [Makofi] 341 00:16:58,902 --> 00:17:01,690 342 00:17:01,690 --> 00:17:04,839 >> --if tunaweza, moja zaidi kama karibu ya hii. 343 00:17:04,839 --> 00:17:07,690 Oh, sasa kila mtu anataka baadhi balbu mwanga. 344 00:17:07,690 --> 00:17:11,790 Kwa kinachojulikana hacker toleo, tunakwenda njia panda it up a-- oh, 345 00:17:11,790 --> 00:17:12,770 yeah, noncommittal. 346 00:17:12,770 --> 00:17:16,010 Nadhani wewe kuja juu sasa kama mkono wako kwenda chini. 347 00:17:16,010 --> 00:17:16,800 Jina lako ni nani? 348 00:17:16,800 --> 00:17:17,424 >> Watazamaji: Alex. 349 00:17:17,424 --> 00:17:19,440 DAVID J. Malan: Alex, kuja juu zaidi ya hapa. 350 00:17:19,440 --> 00:17:26,190 Hivyo kwa Alex, sisi ni kwenda mpango katika idadi kubwa kidogo. 351 00:17:26,190 --> 00:17:27,790 Pengine katika utaratibu. 352 00:17:27,790 --> 00:17:29,110 simu ya 50. 353 00:17:29,110 --> 00:17:29,744 >> Watazamaji: OK. 354 00:17:29,744 --> 00:17:31,660 DAVID J. Malan: Lakini, kama Mimi said-- na unaweza 355 00:17:31,660 --> 00:17:33,580 wanataka kusimama hapa ili kwamba vifungo kujipanga 356 00:17:33,580 --> 00:17:37,115 kama ungependa expect-- lakini mimi wito huu hacker toleo. 357 00:17:37,115 --> 00:17:47,125 So-- bahati nzuri! 358 00:17:47,125 --> 00:17:48,416 >> [Kicheko] 359 00:17:48,416 --> 00:17:58,570 360 00:17:58,570 --> 00:18:02,050 >> Utakuwa na uwezo wa kugeuka yao mbali kama you-- OK. 361 00:18:02,050 --> 00:18:02,880 Excellent. 362 00:18:02,880 --> 00:18:03,675 Ajabu. 363 00:18:03,675 --> 00:18:04,341 Hongera. 364 00:18:04,341 --> 00:18:08,730 >> [Makofi] 365 00:18:08,730 --> 00:18:10,355 Mimi nadhani wanapaswa kulipa up. 366 00:18:10,355 --> 00:18:11,830 Hongera kwa Alex kama vizuri. 367 00:18:11,830 --> 00:18:12,330 OK. 368 00:18:12,330 --> 00:18:15,550 >> Hivyo takeaway mwisho hapa ni hopefully, kusema ukweli, 369 00:18:15,550 --> 00:18:18,109 simplicity-- unyenyekevu na ambayo 370 00:18:18,109 --> 00:18:20,650 unaweza kupata baadhi ya mwanga nzuri balbu, inaonekana katika [inaudible]. 371 00:18:20,650 --> 00:18:23,000 Lakini wao kuwakilisha, mawazo hatimaye, sawa 372 00:18:23,000 --> 00:18:26,310 ambayo sisi binadamu ni tayari wote pia familiar. 373 00:18:26,310 --> 00:18:28,660 Hivyo, nini kinaweza ijayo hatua kuwa katika maendeleo 374 00:18:28,660 --> 00:18:30,920 ya kujaribu kufanya kitu kuvutia na data 375 00:18:30,920 --> 00:18:34,950 na pembejeo ambazo anayewakilisha si tu namba lakini ni labda barua au zaidi? 376 00:18:34,950 --> 00:18:37,820 >> Naam, zinageuka kuwa dunia ya kompyuta, kwa miaka mingi, 377 00:18:37,820 --> 00:18:43,300 tu iliyopitishwa holela lakini standard thabiti kwamba ramani namba 378 00:18:43,300 --> 00:18:44,610 kwa herufi za alfabeti. 379 00:18:44,610 --> 00:18:47,120 Kwa mfano, hapa ni Excerpt kutoka ramani hiyo. 380 00:18:47,120 --> 00:18:48,350 Ni wito ASCII. 381 00:18:48,350 --> 00:18:53,220 -S-C-I-I. Na kwamba ni tu meza kwamba ramani uppercase letters-- 382 00:18:53,220 --> 00:18:56,600 katika hii case-- kwa namba decimal. 383 00:18:56,600 --> 00:18:57,890 >> Lakini nini maana? 384 00:18:57,890 --> 00:19:01,090 Naam, kama wewe kweli unataka kuwakilisha kitu kama barua pepe au baadhi ya maandishi 385 00:19:01,090 --> 00:19:03,310 juu ya ukurasa wa mtandao, unaweza wazi wanataka kuonyesha 386 00:19:03,310 --> 00:19:06,100 barua za binadamu za alfabeti, si idadi. 387 00:19:06,100 --> 00:19:09,140 Hivyo kutegemea mazingira ya mpango 388 00:19:09,140 --> 00:19:12,600 kwamba mtumiaji ni kwa kutumia, ikiwa ni kivinjari au email mteja, 389 00:19:12,600 --> 00:19:16,090 namba tunaweza kuwa kufasiriwa kama barua. 390 00:19:16,090 --> 00:19:20,290 Hiyo ni kusema, mifumo ya bits unaweza kwa urahisi kutafsiriwa kama barua. 391 00:19:20,290 --> 00:19:24,700 >> Na hivyo kile tunaweza kuwa na ni barua kiumbe 392 00:19:24,700 --> 00:19:28,410 kuwakilishwa kama 65, B kuwa kuwakilishwa kama 66. 393 00:19:28,410 --> 00:19:30,900 Hivyo kama tuna super neno short, kama hi, 394 00:19:30,900 --> 00:19:35,740 nini kompyuta ingekuwa hatimaye duka katika decimal lakini kwa kweli katika binary, 395 00:19:35,740 --> 00:19:40,070 kutumia baadhi ya mlolongo wa bits, leveraging kidogo ya umeme katika baadhi ya njia, 396 00:19:40,070 --> 00:19:44,010 itakuwa namba mbili 72 na 73. 397 00:19:44,010 --> 00:19:46,780 >> Lakini mfano wa bits kwamba inawakilisha maadili hayo. 398 00:19:46,780 --> 00:19:49,820 Basi hao kisha ni jinsi gani tunaweza kuwakilisha pembejeo yetu na mazao. 399 00:19:49,820 --> 00:19:52,630 Na inatosha kusema, tunaweza kufanya uwakilishi ngumu zaidi 400 00:19:52,630 --> 00:19:56,450 hatimaye pamoja na mambo kama graphics, video, muziki, na zaidi 401 00:19:56,450 --> 00:19:58,190 kama tutaweza kuona baadaye muda huu. 402 00:19:58,190 --> 00:20:00,630 >> Hivyo kwamba tu majani kisha algorithms, seti hizi 403 00:20:00,630 --> 00:20:03,490 ya maelekezo ambayo sisi ni kutatua matatizo halisi. 404 00:20:03,490 --> 00:20:05,820 Sisi ni kupita katika pembejeo kwa algorithms. 405 00:20:05,820 --> 00:20:09,630 Na algorithms wale ni kuzalisha matokeo, matokeo hopefully sahihi 406 00:20:09,630 --> 00:20:14,160 na hopefully, pia, ufanisi wamekusanyika mazao. 407 00:20:14,160 --> 00:20:16,890 Kwa maneno mengine, ni jambo moja kutekeleza kitu kwa usahihi. 408 00:20:16,890 --> 00:20:20,790 Ni jambo lingine kutekeleza ni kitu vizuri au kwa ufanisi. 409 00:20:20,790 --> 00:20:23,690 >> Kwa mfano, moja maandamano kwamba sisi ni uzoefu wa katika mwendo 410 00:20:23,690 --> 00:20:24,460 ni hii moja. 411 00:20:24,460 --> 00:20:26,345 Lakini hayo ni kupata inazidi vigumu kupata. 412 00:20:26,345 --> 00:20:28,930 Lakini hii ni kweli umri wa shule ya kitabu cha simu, ndani ya ambayo 413 00:20:28,930 --> 00:20:32,580 ni 1,000 plus kurasa za majina na namba za simu. 414 00:20:32,580 --> 00:20:34,830 Na kama mimi alitaka kuangalia up mtu katika hii kitabu cha simu, 415 00:20:34,830 --> 00:20:38,640 Mimi naweza tu kufanya naive sana algorithm. 416 00:20:38,640 --> 00:20:42,150 Mimi naweza kufungua kwa ukurasa wa kwanza, na Mimi naweza kuanza kuangalia kwa, kusema, mtu 417 00:20:42,150 --> 00:20:43,130 aitwaye Mike Smith. 418 00:20:43,130 --> 00:20:46,160 Na kama yeye si juu ya kwanza ukurasa, mimi maendeleo ya pili, 419 00:20:46,160 --> 00:20:49,120 na kisha tatu, na kisha ya nne, na kadhalika, 420 00:20:49,120 --> 00:20:51,430 mpaka mimi hatimaye kupata Mike Smith. 421 00:20:51,430 --> 00:20:53,010 >> Sasa ni kwamba algorithm sahihi? 422 00:20:53,010 --> 00:20:53,896 >> Watazamaji: Ndiyo. 423 00:20:53,896 --> 00:20:54,248 >> DAVID J. Malan: Yeah. 424 00:20:54,248 --> 00:20:56,039 Kama yeye ni katika huko, mimi itabidi hatimaye kupata naye. 425 00:20:56,039 --> 00:20:58,820 Lakini ni arguably si sana ufanisi, hakika si kwa kasi, 426 00:20:58,820 --> 00:21:01,200 kwa sababu, mungu wangu, kwa nini ningali kupoteza muda wangu flipping 427 00:21:01,200 --> 00:21:04,500 kwa njia zote za kurasa hizi wakati mimi naweza hakika kufanya hivyo kimwili kasi? 428 00:21:04,500 --> 00:21:08,210 >> Naam, optimization kidogo, hivyo kusema, inaweza kuwa si moja ukurasa kwa wakati, 429 00:21:08,210 --> 00:21:11,610 lakini mbili, nne, sita, nane, 10. 430 00:21:11,610 --> 00:21:12,725 Bado ni sahihi? 431 00:21:12,725 --> 00:21:14,030 >> Watazamaji: Hapana 432 00:21:14,030 --> 00:21:17,040 >> DAVID J. Malan: Hivyo hakuna kama mimi kwa mfano ruka juu ya Mike Smith. 433 00:21:17,040 --> 00:21:20,530 Lakini muda mrefu kama mimi nyuma kanyagio ukurasa mmoja, kama mimi overshoot yake, 434 00:21:20,530 --> 00:21:25,240 labda tunaweza kusahihisha kile kinacho pengine wanaweza kuwa gotcha. 435 00:21:25,240 --> 00:21:26,020 >> Lakini ni bora? 436 00:21:26,020 --> 00:21:27,469 Je, ni kasi? 437 00:21:27,469 --> 00:21:28,010 I mean, yeah. 438 00:21:28,010 --> 00:21:30,950 Ni literally mara mbili kwa haraka kama mimi kufanya kurasa mbili kwa wakati. 439 00:21:30,950 --> 00:21:35,720 Hivyo kama Mimi awali alikuwa kurasa 1,000, sasa mimi tu flip mara 500, 440 00:21:35,720 --> 00:21:39,429 si kikamilifu kurasa 1,000 kwa kupata uwezekano wa katika kesi mbaya 441 00:21:39,429 --> 00:21:41,220 hadi mwisho wa simu kitabu, ambapo mtu 442 00:21:41,220 --> 00:21:44,380 kama Mike Smith au mtu aliye na jina baadaye ili kweli kuwa. 443 00:21:44,380 --> 00:21:46,540 >> Lakini, bila shaka, sisi binadamu hakika si 444 00:21:46,540 --> 00:21:49,250 kwenda kufanya kwamba, hakika si katika hatua hii katika maisha yetu. 445 00:21:49,250 --> 00:21:51,454 Nini ni ya kuridhisha binadamu uwezekano wa kwenda kufanya nini? 446 00:21:51,454 --> 00:21:52,870 Watazamaji: Nenda moja kwa moja kwa the9 ya S. 447 00:21:52,870 --> 00:21:53,860 DAVID J. Malan: Nenda moja kwa moja kwa ya S? 448 00:21:53,860 --> 00:21:55,563 Je, mimi kwenda moja kwa moja ya S? 449 00:21:55,563 --> 00:21:57,342 >> Watazamaji: Mpasuko katika nusu. 450 00:21:57,342 --> 00:21:59,050 DAVID J. Malan: Sawa, hakuna kuashiria. 451 00:21:59,050 --> 00:22:02,116 Kwa hiyo, ndiyo, kama kulikuwa na kweli studio au tab nata kwa S, 452 00:22:02,116 --> 00:22:03,240 sisi lazima kuruka haki pale. 453 00:22:03,240 --> 00:22:05,420 Lakini ni pretty innocuous. 454 00:22:05,420 --> 00:22:08,480 Hivyo bora naweza kufanya ni takribani kwa S sehemu au labda takribani 455 00:22:08,480 --> 00:22:09,650 ndani ya katikati. 456 00:22:09,650 --> 00:22:12,110 Lakini takeaway muhimu now-- na Intuition 457 00:22:12,110 --> 00:22:14,430 kwamba umechukua kwa nafasi kwa miaka probably-- 458 00:22:14,430 --> 00:22:17,103 ni kwamba nini wewe sasa kujua kuhusu tatizo hili? 459 00:22:17,103 --> 00:22:19,320 >> Watazamaji: [inaudible] 460 00:22:19,320 --> 00:22:22,290 >> DAVID J. Malan: Mike Smith ni hakika si katika hii nusu ya tatizo 461 00:22:22,290 --> 00:22:25,600 kwa sababu Smith inakuja baada ya katikati ambayo ni takribani sehemu M, 462 00:22:25,600 --> 00:22:26,510 inaonekana kuwa. 463 00:22:26,510 --> 00:22:30,340 Hivyo kama unaweza kuwa na kuonekana katika Visitas, tunaweza sasa literally 464 00:22:30,340 --> 00:22:31,737 machozi tatizo hili katika nusu. 465 00:22:31,737 --> 00:22:32,320 Watazamaji: Woo! 466 00:22:32,320 --> 00:22:33,690 DAVID J. Malan: Ni kupata rahisi na rahisi zaidi. 467 00:22:33,690 --> 00:22:34,666 [Makofi] 468 00:22:34,666 --> 00:22:36,618 Kuna kwenda. 469 00:22:36,618 --> 00:22:39,060 [Kicheko] 470 00:22:39,060 --> 00:22:41,870 Na sasa mimi kimsingi kuwa na tatizo moja, 471 00:22:41,870 --> 00:22:43,866 lakini ni literally nusu kama kubwa. 472 00:22:43,866 --> 00:22:45,240 Mimi bado kuangalia kwa Mike Smith. 473 00:22:45,240 --> 00:22:47,950 Na mimi daresay, mimi bado unaweza kuangalia kwa ajili yake katika njia hiyo hiyo, 474 00:22:47,950 --> 00:22:51,200 kugawanyika tatizo katika nusu tena, akamtikisatikisa tatizo tena 475 00:22:51,200 --> 00:22:54,140 katika nusu, ambayo sasa mimi majani na tatizo robo ya kawaida, 476 00:22:54,140 --> 00:22:58,710 kasi kutupa kwamba nusu mbali, na kurudia utaratibu huu tena na tena 477 00:22:58,710 --> 00:23:01,150 na tena, glancing chini katika kila hatua kuona 478 00:23:01,150 --> 00:23:03,400 kama Mike Smith ni juu ya ukurasa katika swali. 479 00:23:03,400 --> 00:23:06,190 >> Sasa kama mimi kufanya haki hii, hatimaye mimi itabidi kupata mwenyewe 480 00:23:06,190 --> 00:23:11,085 kwa ukurasa moja tu ambayo Mike Smith ni kama yeye ni kweli katika kitabu cha simu. 481 00:23:11,085 --> 00:23:13,510 Bila shaka, mimi naweza kamwe wito Mike tena. 482 00:23:13,510 --> 00:23:18,800 Lakini uhakika hapa ni kwamba kama sisi kuanza na kurasa 1,000, algorithm yangu ya kwanza, 483 00:23:18,800 --> 00:23:21,620 flip ukurasa, labda 1000 times-- dhahiri chini kwa sababu ni 484 00:23:21,620 --> 00:23:26,430 Jina S na si Z jina, lakini kama kurasa nyingi kama 1,000 uwezekano. 485 00:23:26,430 --> 00:23:27,590 >> Algorithm Pili, bora. 486 00:23:27,590 --> 00:23:28,480 Kurasa 500. 487 00:23:28,480 --> 00:23:31,230 Algorithm Tatu, ingawa, jinsi hatua nyingi ingekuwa ni 488 00:23:31,230 --> 00:23:35,520 kuchukua kugawanya ukurasa 1000 kitabu cha simu katika nusu kama hayo? 489 00:23:35,520 --> 00:23:37,000 10, kutoa au kuchukua. 490 00:23:37,000 --> 00:23:40,770 Hivyo tu kwa flipping kupitia kwamba kitabu cha simu, mbizi na mshindi, 491 00:23:40,770 --> 00:23:46,130 hivyo kusema, mara 10, nitamfanya kuwa njia yangu chini ya single ukurasa moja tu. 492 00:23:46,130 --> 00:23:48,880 >> Na ili tuweze kukamata Intuition hii sasa kidogo graphically 493 00:23:48,880 --> 00:23:51,320 kama wewe tu kufikiria hii graph super rahisi. 494 00:23:51,320 --> 00:23:55,470 Sisi ni juu ya x-mhimili, au usawa mhimili, ni ukubwa wa tatizo langu, 495 00:23:55,470 --> 00:23:57,100 idadi ya kurasa katika kitabu cha simu. 496 00:23:57,100 --> 00:23:59,040 Na wanasayansi wa kompyuta kwa ujumla kama kuwaita 497 00:23:59,040 --> 00:24:02,180 ukubwa wa tatizo n, ambapo n ni baadhi tu ya variable kwamba 498 00:24:02,180 --> 00:24:04,310 represents-- katika hii case-- idadi ya kurasa. 499 00:24:04,310 --> 00:24:07,412 >> wima, au y-mhimili, hapa ni kwenda kuwa wakati kutatua, 500 00:24:07,412 --> 00:24:09,870 labda ya simu ya ukurasa zamu, labda idadi ya sekunde 501 00:24:09,870 --> 00:24:11,960 au dakika, chochote kitengo yako ya kipimo ni. 502 00:24:11,960 --> 00:24:14,337 Na hivyo mstari huu nyekundu inawakilisha algorithm kwanza, 503 00:24:14,337 --> 00:24:16,670 kwa sababu kuna 12:59 uhusiano kati ya idadi 504 00:24:16,670 --> 00:24:18,880 ya kurasa na kiasi cha muda inachukua. 505 00:24:18,880 --> 00:24:22,240 >> Kama Verizon mara mbili idadi ya kurasa katika kitabu cha simu mwaka ujao, 506 00:24:22,240 --> 00:24:24,590 mbio yangu time-- muda unaotakiwa ili kutekeleza 507 00:24:24,590 --> 00:24:27,610 kwamba algorithm-- kwanza mara mbili katika kesi mbaya. 508 00:24:27,610 --> 00:24:30,690 Lakini algorithm ya pili, ambapo mimi nina flipping na mbili, 509 00:24:30,690 --> 00:24:33,650 inahitaji muda kidogo kwa ajili ya kutokana na ukubwa tatizo. 510 00:24:33,650 --> 00:24:36,090 Hivyo kama mimi kuwa na hii wengi ilani kurasa here-- 511 00:24:36,090 --> 00:24:38,870 kwamba line njano unaonyesha chini ya muda kutatua. 512 00:24:38,870 --> 00:24:42,490 Na hakika, inawakilisha, tutaweza kusema, n juu ya mbili. 513 00:24:42,490 --> 00:24:47,717 >> Lakini nini sura ya tatu na Curve ya mwisho kwenda kuangalia kama? 514 00:24:47,717 --> 00:24:50,800 Yeah, ni kweli kwenda look-- mimi hawajui nini walikuwa kwenda kusema. 515 00:24:50,800 --> 00:24:52,300 Lakini hebu angalia nini wewe walikuwa kwenda kusema. 516 00:24:52,300 --> 00:24:53,280 >> Watazamaji: Kama hiyo. 517 00:24:53,280 --> 00:24:57,060 >> DAVID J. Malan: Ni kwenda kuangalia kama hii, logarithmic slope-- exactly-- 518 00:24:57,060 --> 00:24:59,770 ambapo una mteremko hii curious. 519 00:24:59,770 --> 00:25:01,235 Ni tena line moja kwa moja. 520 00:25:01,235 --> 00:25:05,000 Na nini kulazimisha juu ya kwamba ni kwamba ingawa graph sasa ni kukatwa, 521 00:25:05,000 --> 00:25:07,790 unaweza extrapolate katika yako akili kwamba line ya kijani si 522 00:25:07,790 --> 00:25:10,060 kwenda kuongeza katika urefu yote kwamba mengi 523 00:25:10,060 --> 00:25:13,500 kama wewe kuendelea zaidi chini kwamba mhimili usawa. 524 00:25:13,500 --> 00:25:15,890 >> Hakika, Verizon, kwa mfano, inaweza mara mbili 525 00:25:15,890 --> 00:25:19,100 idadi ya kurasa katika simu kitabu kati ya mwaka huu na mwaka ujao 526 00:25:19,100 --> 00:25:22,140 kutoka 1,000 hadi 2000 kurasa, lakini hakuna mpango mkubwa. 527 00:25:22,140 --> 00:25:24,960 Pamoja na hii ya tatu na ya mwisho, kuna algorithm Intuitive 528 00:25:24,960 --> 00:25:26,209 ya kugawa na Mshindi. 529 00:25:26,209 --> 00:25:29,000 Ni kwenda kuchukua yangu jinsi wengi zaidi hatua ya mwaka ujao kwa kupata mtu 530 00:25:29,000 --> 00:25:29,700 kama Mike Smith? 531 00:25:29,700 --> 00:25:30,560 >> Watazamaji: One. 532 00:25:30,560 --> 00:25:31,230 >> DAVID J. Malan: Kuna moja tu. 533 00:25:31,230 --> 00:25:34,430 Na wanaweza quadruple yake, ni anaenda kuchukua yangu hatua mbili tu zaidi 534 00:25:34,430 --> 00:25:35,210 na kadhalika. 535 00:25:35,210 --> 00:25:38,730 Na hivyo hii ni ushahidi wa tu jinsi baadhi kubuni makini 536 00:25:38,730 --> 00:25:42,437 na baadhi ya shukrani kwa ajili ya nini pembejeo yako ni unaweza kufanya hata bora. 537 00:25:42,437 --> 00:25:44,270 Sasa sisi ni cheating kidogo kwa maana ya 538 00:25:44,270 --> 00:25:46,350 kwamba sisi ni leveraging dhana. 539 00:25:46,350 --> 00:25:48,500 Ni dhana yangu ni nini kuhusu kitabu yetu ya simu 540 00:25:48,500 --> 00:25:52,720 ambayo imesababisha mimi kugawanya na kushinda kwa njia hii Intuitive na bado ni sahihi? 541 00:25:52,720 --> 00:25:53,705 >> Watazamaji: [inaudible] 542 00:25:53,705 --> 00:25:54,580 DAVID J. Malan: Yeah. 543 00:25:54,580 --> 00:25:55,440 Hivyo ilikuwa aliamuru. 544 00:25:55,440 --> 00:25:57,392 Ilikuwa alphabetized na kitabu cha simu kampuni. 545 00:25:57,392 --> 00:26:00,100 Kama ilivyokuwa ili random, kwamba itakuwa kuzimu ya kitabu cha simu, 546 00:26:00,100 --> 00:26:02,850 lakini ni hakika bila mikopo yenyewe kwa algorithm 547 00:26:02,850 --> 00:26:05,950 Mimi kutumika, kwa sababu wewe ungekuwa kamwe kutokea tu katika Mike Smith 548 00:26:05,950 --> 00:26:09,210 kama wewe naendelea kugawa katika nusu kwa njia hiyo kwa nafasi. 549 00:26:09,210 --> 00:26:12,060 >> Basi hebu sasa kurasimisha nini wazi Intuitive. 550 00:26:12,060 --> 00:26:13,950 Hivyo kitu kinachoitwa pseudocode ni ambapo tutaweza 551 00:26:13,950 --> 00:26:15,780 kuanza baadhi ya matatizo yetu ya awali. 552 00:26:15,780 --> 00:26:20,410 Na hii ni njia generic ya kuelezea algorithm au programu ya kompyuta, 553 00:26:20,410 --> 00:26:24,150 si kwa kutumia C, au C ++, au Java, au lugha yoyote maalum, 554 00:26:24,150 --> 00:26:27,430 lakini tu kwa kutumia lugha ya Kiingereza, na ambayo binadamu yeyote anaweza kuwa na mazoea. 555 00:26:27,430 --> 00:26:31,220 >> Na tupate kuandika pseudocode kwa tatizo hili kama ifuatavyo. 556 00:26:31,220 --> 00:26:33,520 Hatua moja, pick up kitabu cha simu. 557 00:26:33,520 --> 00:26:35,840 Hatua mbili, wazi katikati ya kitabu cha simu. 558 00:26:35,840 --> 00:26:37,730 Hatua ya tatu, kuangalia majina. 559 00:26:37,730 --> 00:26:40,630 Hatua ya nne, kama Smith ni kati ya names-- 560 00:26:40,630 --> 00:26:42,960 >> Na sasa hii ni kuvutia kujenga. 561 00:26:42,960 --> 00:26:44,290 Ni hatua uamuzi. 562 00:26:44,290 --> 00:26:47,920 Ni uma katika barabara, kama wewe itakuwa, tawi, hivyo kusema. 563 00:26:47,920 --> 00:26:50,810 Hivyo nina kwenda kwa Indent tu kwa mkataba step-- 564 00:26:50,810 --> 00:26:53,950 si five-- ambayo ni kwa kusema, mimi itabidi kuwaita Mike. 565 00:26:53,950 --> 00:26:57,290 Hivyo indentation hii, kabisa mkataba holela binadamu, lakini ni 566 00:26:57,290 --> 00:27:01,160 tu maana ya kufikisha semantically kwamba kama Smith ni miongoni mwa majina, 567 00:27:01,160 --> 00:27:03,310 basi mimi lazima wito Mike. 568 00:27:03,310 --> 00:27:06,630 >> Wakati huo huo katika hatua sita, taarifa kwamba indentation gone. 569 00:27:06,630 --> 00:27:10,980 Hivyo kingine ni uma nyingine katika barabara, barabara nyingine nipate kusafiri. 570 00:27:10,980 --> 00:27:14,130 Hivyo mwingine kama Smith ni mapema katika kitabu, nini 571 00:27:14,130 --> 00:27:16,964 hatua yangu ya pili pengine ni kwenda kuwa hapa? 572 00:27:16,964 --> 00:27:18,380 Watazamaji: Unaweza kwenda kwa upande wa kushoto. 573 00:27:18,380 --> 00:27:21,004 DAVID J. Malan: Yeah, hivyo kwenda kwa nusu ya kushoto ya kitabu cha simu. 574 00:27:21,004 --> 00:27:24,140 Kutupa mbali nusu haki kama Smith ni mapema katika kitabu. 575 00:27:24,140 --> 00:27:27,140 Hivyo wazi katikati ya nusu ya kushoto ya kitabu. 576 00:27:27,140 --> 00:27:30,240 >> Na kisha hatua nane, kwenda mstari tatu. 577 00:27:30,240 --> 00:27:34,520 Na hii ni curious kitanzi mimi nina inducing, kujirudia hivyo kusema. 578 00:27:34,520 --> 00:27:35,990 Lakini zaidi juu ya kwamba katika siku zijazo. 579 00:27:35,990 --> 00:27:39,590 >> Mimi nina kutumia algorithm yangu huo, pseudocode yangu huo, 580 00:27:39,590 --> 00:27:43,020 kutatua tatizo moja tena kwa sababu jambo tu hiyo ni iliyopita 581 00:27:43,020 --> 00:27:46,550 ni ukubwa wa tatizo, si lengo langu, na si mtu 582 00:27:46,550 --> 00:27:47,340 Mimi nina kuangalia kwa. 583 00:27:47,340 --> 00:27:51,610 Hivyo siwezi kutumia tena algorithm kwamba nimepata tayari defined. 584 00:27:51,610 --> 00:27:53,580 >> Mwingine kama Smith ni baadaye katika book-- waweza 585 00:27:53,580 --> 00:27:56,200 guess-- wazi katikati ya nusu haki ya kitabu. 586 00:27:56,200 --> 00:27:58,350 Na tena, kwenda mstari tatu. 587 00:27:58,350 --> 00:28:01,480 Else-- ni nini mstari wa mwisho katika mpango huu kwenda kuwa? 588 00:28:01,480 --> 00:28:03,580 Kama yeye si miongoni mwa majina ya ukurasa mimi nina 589 00:28:03,580 --> 00:28:06,870 juu, kama yeye si mapema katika kitabu, na yeye si baadaye 590 00:28:06,870 --> 00:28:09,899 katika kitabu, je, Mimi najua ni kweli kuhusu Mike Smith sasa? 591 00:28:09,899 --> 00:28:11,190 Watazamaji: Yeye si katika kitabu. 592 00:28:11,190 --> 00:28:12,731 DAVID J. Malan: Yeye si katika kitabu. 593 00:28:12,731 --> 00:28:16,040 Hivyo bora naweza kufanya ni tu kutoa up na kuacha mpango huu. 594 00:28:16,040 --> 00:28:16,540 Wote haki. 595 00:28:16,540 --> 00:28:20,350 Hivyo katika hatua hii, hebu kuchukua ziara ya haraka ya baadhi ya nini watapata. 596 00:28:20,350 --> 00:28:23,620 Na kwa kweli, mimi nina alijiunga hapa na idadi ya CS50 wafanyakazi. 597 00:28:23,620 --> 00:28:26,940 Kama folks hizi inaweza wote kujiunga na me up hapa juu ya hatua. 598 00:28:26,940 --> 00:28:28,900 >> [Makofi] 599 00:28:28,900 --> 00:28:35,280 600 00:28:35,280 --> 00:28:38,170 >> Kumbuka, hii ni tu subset ya CS50 wafanyakazi, 601 00:28:38,170 --> 00:28:42,380 tangu kila mwaka tuna karibu 100 wafanyakazi wanachama katika majukumu bila shaka wasaidizi, 602 00:28:42,380 --> 00:28:44,410 kufundisha wenzake, na zaidi. 603 00:28:44,410 --> 00:28:45,700 Kuja juu juu. 604 00:28:45,700 --> 00:28:48,820 Hivyo wao kujiunga na sisi hapa awkwardly kwa muda tu 605 00:28:48,820 --> 00:28:54,230 kama sisi kutoa kimbunga ziara ya nini unapaswa kutarajia hapa katika shaka. 606 00:28:54,230 --> 00:28:59,640 >> Hivyo kwanza kabisa, tuna SAT / UNS kama chaguo grading katika shaka. 607 00:28:59,640 --> 00:29:03,180 Hii ni maana kwa makusudi kuwa chaguo ambapo 608 00:29:03,180 --> 00:29:05,570 kama wewe ni kidogo uneasy kutokana na kuwa katika shaka, 609 00:29:05,570 --> 00:29:09,390 na huna hofu failure-- hata kama kusema ukweli kushindwa ina maana kuumiza GPA yako, 610 00:29:09,390 --> 00:29:13,180 kupata B na si A-- kwamba ni just nini, hakika kwa gateway 611 00:29:13,180 --> 00:29:15,750 Bila shaka kama CS50 na wengine masomo ya awali, 612 00:29:15,750 --> 00:29:17,540 chaguo hili grading ni maana ya kuruhusu. 613 00:29:17,540 --> 00:29:19,930 >> Mimi kwa moyo wote kuhamasisha students-- hasa 614 00:29:19,930 --> 00:29:23,090 kama juu ya fence-- kuanza Bila shaka SAT / UNS, hata kubaki SAT / UNS. 615 00:29:23,090 --> 00:29:27,310 Lakini unaweza shaka kubadili barua daraja na tano ya Jumatatu katika muda mrefu. 616 00:29:27,310 --> 00:29:31,560 >> Kwa kweli, nyuma wakati mimi mara freshman mwaka 1995, 617 00:29:31,560 --> 00:29:34,630 Mimi mwenyewe hakuwa hata kuchukua CS50 kwa sababu sikuweza kupata up ujasiri 618 00:29:34,630 --> 00:29:36,540 kwa kweli hatua ya mguu darasani. 619 00:29:36,540 --> 00:29:40,020 Ilionekana domain mbali sana unfamiliar kwangu na kwa kweli tu 620 00:29:40,020 --> 00:29:43,080 kwa wale marafiki zangu, kusema ukweli, ambaye amekuwa programu 621 00:29:43,080 --> 00:29:45,570 kwa vile wao walikuwa six- au labda-miaka 10 miaka. 622 00:29:45,570 --> 00:29:48,640 Na ilikuwa tu kwa sababu nilikuwa uwezo wa kuchukua CS50 katika siku yangu 623 00:29:48,640 --> 00:29:52,720 katika sawa toleo la SAT / UNS-- kupita / kushindwa nyuma katika day-- 624 00:29:52,720 --> 00:29:53,850 kwamba hata mimi alichukua 50. 625 00:29:53,850 --> 00:29:57,440 Na kwa namna fulani au nyingine, mimi nina hapa tena na wewe leo. 626 00:29:57,440 --> 00:30:00,690 >> Sasa wakati huo huo kile kingine unapaswa kukumbuka juu ya 50 627 00:30:00,690 --> 00:30:01,910 ni uandikishaji samtidiga. 628 00:30:01,910 --> 00:30:03,785 Kinyume na uvumi kuwa unaweza kuwa na habari, 629 00:30:03,785 --> 00:30:07,650 unaweza, kwa kweli, wakati huo huo kujiandikisha katika CS50 na darasa lingine kwamba 630 00:30:07,650 --> 00:30:12,150 hukutana saa moja au baadhi ukipishana wakati kama mihadhara CS50 ya haki hapa. 631 00:30:12,150 --> 00:30:16,420 Angalia mtaala kwa maelezo ya utekelezaji wake. 632 00:30:16,420 --> 00:30:19,540 >> Mihadhara, wakati huo huo, kinyume na nini rasmi katika catalog, 633 00:30:19,540 --> 00:30:22,060 mapenzi kwa ujumla tu kukutana kwa ajili ya saa moja tu. 634 00:30:22,060 --> 00:30:24,240 Katika tukio tunaweza kukimbia kidogo kwa muda mrefu. 635 00:30:24,240 --> 00:30:26,800 Lakini kukumbuka kwamba lengo katika mihadhara CS50 ya 636 00:30:26,800 --> 00:30:28,980 ni kutoa kwa maelezo ya jumla dhana, 637 00:30:28,980 --> 00:30:31,830 hopefully maandamano baadhi, labda hata baadhi giveaways, 638 00:30:31,830 --> 00:30:34,390 ya nini watapata kwa wiki kwamba ifuatavyo. 639 00:30:34,390 --> 00:30:37,730 >> Na hivyo katika mihadhara, tutaweza kuchunguza wale mada na mifano pamoja, 640 00:30:37,730 --> 00:30:41,420 kuleta ya wanafunzi juu ya hatua, na wafanyakazi juu ya hatua kama mara nyingi kama tunaweza, 641 00:30:41,420 --> 00:30:43,740 kwa michache tu ya masaa kila wiki. 642 00:30:43,740 --> 00:30:47,435 Sehemu, wakati huo huo, itakuwa inayotolewa na folks haya here-- wengi 643 00:30:47,435 --> 00:30:50,060 wao kufundisha wenzake, baadhi wao bila shaka assistants-- mapenzi 644 00:30:50,060 --> 00:30:51,160 kuwa kinachotokea kila wiki. 645 00:30:51,160 --> 00:30:52,940 >> Na nini muhimu kuweka katika akili ni kwamba sisi 646 00:30:52,940 --> 00:30:55,920 je have-- tofauti Kwanza si Nights, muziki class-- 647 00:30:55,920 --> 00:30:59,220 nyimbo tofauti ya sehemu kwa ajili ya wanafunzi chini ya starehe, zaidi 648 00:30:59,220 --> 00:31:01,150 vizuri, na mahali fulani katika kati ya. 649 00:31:01,150 --> 00:31:03,559 Na kusema ukweli, wewe kujua kama wewe ni chini ya starehe. 650 00:31:03,559 --> 00:31:05,600 Na pengine kujua kama wewe ni vizuri zaidi. 651 00:31:05,600 --> 00:31:09,920 Na kama wewe ni kweli sina uhakika, wewe ni kwa ufafanuzi mahali fulani katika kati ya. 652 00:31:09,920 --> 00:31:12,850 Hivyo linapokuja suala la muda wa kifungu cha katika wiki au hivyo, kwa mitaala, 653 00:31:12,850 --> 00:31:14,070 tutakuuliza swali hilo. 654 00:31:14,070 --> 00:31:16,890 Na unaweza binafsi kuchagua Based juu ya faraja yako mwenyewe ngazi 655 00:31:16,890 --> 00:31:22,220 na kuwa na students-- kuwa na kijani dots-- sawa katika faraja ngazi na wewe. 656 00:31:22,220 --> 00:31:25,710 >> Wakati huo huo, tuna tatizo seti, ambayo itakuwa hatimaye 657 00:31:25,710 --> 00:31:28,310 kufafanua uzoefu wako katika kozi hii. 658 00:31:28,310 --> 00:31:30,370 Wao ni inayotolewa kwa kawaida katika matoleo mbalimbali. 659 00:31:30,370 --> 00:31:34,150 toleo la kawaida kwamba sisi kutarajia wengi kila mwanafunzi katika kozi ya kukabiliana na 660 00:31:34,150 --> 00:31:37,900 lakini pia kinachojulikana hacker toleo ambayo inatoa hakuna namna ya mikopo ya ziada 661 00:31:37,900 --> 00:31:41,980 wazi lakini kwa kweli haki za majisifu kusema kuwa walijaribu na kukabiliana 662 00:31:41,980 --> 00:31:45,250 Bila shaka ya hacker matoleo kwamba mbinu nyenzo sawa 663 00:31:45,250 --> 00:31:47,370 lakini kutoka angle kisasa zaidi. 664 00:31:47,370 --> 00:31:49,480 >> Nini sisi kutoa kwa toleo la kawaida, kwa, 665 00:31:49,480 --> 00:31:51,420 tena, wengi super ya wanafunzi, ni si 666 00:31:51,420 --> 00:31:54,060 tu kutembea-throughs, ambayo ni videos wakiongozwa na wafanyakazi bila shaka ya 667 00:31:54,060 --> 00:31:57,840 kwamba kweli kutembea wewe kupitia matatizo bila shaka na kubuni inawezekana 668 00:31:57,840 --> 00:31:58,910 utekelezaji. 669 00:31:58,910 --> 00:32:01,434 Na sisi pia, baada ya kweli, kutoa postmortems, 670 00:32:01,434 --> 00:32:03,350 ambapo kama wewe wanashangaa jinsi gani unaweza kuwa na 671 00:32:03,350 --> 00:32:05,930 au lazima kuwa na kutatuliwa baadhi tatizo, wafanyakazi wa kufundisha 672 00:32:05,930 --> 00:32:08,640 kutembea wewe kupitia wale juu ya video kama vizuri. 673 00:32:08,640 --> 00:32:14,350 >> Wakati huo huo, nini watapata pia ni siku tano marehemu na ukweli 674 00:32:14,350 --> 00:32:16,680 kwamba sisi kushuka yako tatizo chini kuweka alama. 675 00:32:16,680 --> 00:32:20,370 Sisi bila ya shaka kufahamu kwamba katika kubadilishana kwa mzigo wa kazi kwamba 50 anatarajia 676 00:32:20,370 --> 00:32:24,020 ya wewe, maisha anapata katika njia wakati mwingine, kama si mara tano. 677 00:32:24,020 --> 00:32:26,150 Na hivyo hii itatoa kidogo ya mabadiliko, 678 00:32:26,150 --> 00:32:29,400 kupanua tarehe ya mwisho yako kutoka, kusema, a Alhamisi saa sita mchana hadi Ijumaa saa sita mchana. 679 00:32:29,400 --> 00:32:33,150 Angalia mtaala kwa maelezo ya utekelezaji wake. 680 00:32:33,150 --> 00:32:34,702 >> Sasa nini sasa anasubiri? 681 00:32:34,702 --> 00:32:36,660 Na ni tu kutokea kwangu sasa kwa muda mrefu tu jinsi 682 00:32:36,660 --> 00:32:38,333 Mimi nina kuwa na wewe guys kusimama hapa juu ya hatua. 683 00:32:38,333 --> 00:32:39,060 >> [Kicheko] 684 00:32:39,060 --> 00:32:41,867 >> DAVID J. Malan: Lakini tutaweza kupata kumaliza climactic kabla ya muda mrefu. 685 00:32:41,867 --> 00:32:43,700 Hivyo kile watapata katika suala ya seti tatizo? 686 00:32:43,700 --> 00:32:47,099 Naam, labda teaser ya kile sisi wote ilivyokuwa mwaka jana na watangulizi wako. 687 00:32:47,099 --> 00:32:49,140 Katika kwanza tatizo seti mwaka jana, sisi ilianzisha 688 00:32:49,140 --> 00:32:51,630 Scratch, graphical lugha ya programu kwamba 689 00:32:51,630 --> 00:32:54,570 inakuwezesha mpango literally na dragging na kuacha vipande puzzle, 690 00:32:54,570 --> 00:32:57,220 kama hayo, ni kukumbusha ya constructs 691 00:32:57,220 --> 00:32:59,260 utaona wiki moja tu hivyo, wakati sisi kubadili 692 00:32:59,260 --> 00:33:01,870 kwa zaidi ya jadi lugha, unaojulikana kama C. 693 00:33:01,870 --> 00:33:03,930 >> Mwaka jana sisi aliendelea kwa kuweka tatizo hili, 694 00:33:03,930 --> 00:33:06,720 kuwashirikisha kwa cryptography, scrambling wa habari 695 00:33:06,720 --> 00:33:10,410 kuitunza kutoka mashirika ya kiserikali au marafiki ' macho kwamba huna wanataka kuona. 696 00:33:10,410 --> 00:33:12,540 Encoded katika hapa ni ujumbe kwamba hivi karibuni wewe 697 00:33:12,540 --> 00:33:15,740 watakuwa na uwezo wa decrypt au de-kinyang'anyiro. 698 00:33:15,740 --> 00:33:17,960 >> Kuzuka na tatizo kuweka mwaka jana, ambayo 699 00:33:17,960 --> 00:33:21,530 wewe kutumia haya programu mpya kupatikana ujuzi wa kweli kutekeleza 700 00:33:21,530 --> 00:33:24,840 mchezo wherein-- kama wewe Huenda unakumbuka kutoka childhood-- 701 00:33:24,840 --> 00:33:28,040 Lengo lilikuwa bash matofali kwamba ni atop screen 702 00:33:28,040 --> 00:33:30,190 hapa, kukusanya alama njiani, 703 00:33:30,190 --> 00:33:35,460 na kutekeleza algorithms yako mwenyewe na ambayo ufumbuzi huu hatimaye 704 00:33:35,460 --> 00:33:37,357 inakuwezesha kucheza mchezo. 705 00:33:37,357 --> 00:33:39,440 Wakati huo huo, baadaye katika muhula, sisi nitakupa 706 00:33:39,440 --> 00:33:43,470 kamusi ya 143,091 maneno ya Kiingereza. 707 00:33:43,470 --> 00:33:46,300 Na wewe kuwa changamoto kuandika mpango kwamba 708 00:33:46,300 --> 00:33:50,260 Spell hundi, hati, na kupakia maneno kwamba wengi katika kumbukumbu 709 00:33:50,260 --> 00:33:52,300 kama ufanisi kama iwezekanavyo. 710 00:33:52,300 --> 00:33:54,240 Kwa ujumla pitting wewe dhidi ya wanafunzi wako 711 00:33:54,240 --> 00:33:56,610 kama wanachagua katika kidogo ya changamoto katika bodi ya kiongozi 712 00:33:56,610 --> 00:34:00,090 kuona ambao wanaweza kutumia fewest sekunde ya mbio wakati, 713 00:34:00,090 --> 00:34:03,550 na idadi fewest ya megabytes ya kumbukumbu, 714 00:34:03,550 --> 00:34:08,659 na kwa kweli faini-tuning programu yako kuwa incredibly rasilimali ufanisi si 715 00:34:08,659 --> 00:34:09,820 wakati tu. 716 00:34:09,820 --> 00:34:13,239 >> Mwaka jana, pia, sisi inaonekana mwishoni wa muhula katika programu ya mtandao. 717 00:34:13,239 --> 00:34:16,230 Na hakika, sisi itabidi kufanya hivyo tena hii mwaka kwa seti tatizo nyingi, 718 00:34:16,230 --> 00:34:20,290 kuanzisha wewe kwa mbinu na mawazo ambayo unaweza kuomba 719 00:34:20,290 --> 00:34:23,489 stadi hizi programu kwa tovuti, tovuti ya nguvu, 720 00:34:23,489 --> 00:34:26,639 Nje kwamba kweli kutatua matatizo na tabia tofauti 721 00:34:26,639 --> 00:34:30,620 na si tu tuli maeneo na habari tuli. 722 00:34:30,620 --> 00:34:32,854 >> mradi wa mwisho hatimaye itakuwa kufafanua, ingawa, 723 00:34:32,854 --> 00:34:34,770 kilele bila shaka kwa ajili ya wanafunzi, ambamo 724 00:34:34,770 --> 00:34:37,228 wewe utakuwa na changamoto ya kutekeleza zaidi kitu chochote cha riba 725 00:34:37,228 --> 00:34:40,590 na wewe, hivyo muda mrefu kama ni kwa namna fulani huchota juu ya masomo bila shaka ya. 726 00:34:40,590 --> 00:34:42,930 >> Na kama wewe aliona katika video mwanzoni, 727 00:34:42,930 --> 00:34:47,340 tutahitimisha muhula kwa CS50 hackathon, ambayo kama, usio wa kawaida, 728 00:34:47,340 --> 00:34:51,420 itaanza saa 7:00 usiku moja na mwisho katika 7:00 asubuhi. 729 00:34:51,420 --> 00:34:53,614 Around 9:00, tutaweza ili katika chakula cha jioni ya kwanza. 730 00:34:53,614 --> 00:34:55,489 Around 1:00, tutaweza ili katika chakula cha jioni ya pili. 731 00:34:55,489 --> 00:34:57,490 Na kama wewe ni bado amesimama saa 5:00 AM, sisi 732 00:34:57,490 --> 00:35:00,320 mapenzi shuttle bus wewe kwa IHOP kwa kifungua kinywa. 733 00:35:00,320 --> 00:35:04,980 >> CS50 Fair, wakati huo huo, ni tukio ambayo pamoja na 2,000 Kitivo, wanafunzi, 734 00:35:04,980 --> 00:35:07,850 na wafanyakazi kutoka katika chuo mapenzi kuja kuona mafanikio yako 735 00:35:07,850 --> 00:35:10,150 katika mwendo na ya mwisho miradi na ubunifu 736 00:35:10,150 --> 00:35:14,960 kwamba kujenga juu ya Laptops yako, desktops, au pengine hata balbu mwanga. 737 00:35:14,960 --> 00:35:17,340 >> Wakati huo huo, masaa ya ofisi na muundo msaada. 738 00:35:17,340 --> 00:35:20,480 Na sasa ingekuwa tumekuwa muda bora kuleta kila up. 739 00:35:20,480 --> 00:35:24,310 >> Ofisi ya masaa utafanyika nne usiku wiki kwa masaa nyingi kila usiku 740 00:35:24,310 --> 00:35:27,710 kwa ujumla 20 hadi 30 ya wafanyakazi bila shaka juu ya ushuru wa forodha katika mara moja 741 00:35:27,710 --> 00:35:31,240 kutoa kwa karibu sana moja-on-moja fursa kwa msaada 742 00:35:31,240 --> 00:35:33,790 kwa seti tatizo bila shaka ya. 743 00:35:33,790 --> 00:35:36,120 Tutoring pia itakuwa inapatikana, hasa 744 00:35:36,120 --> 00:35:39,630 kwa ajili ya wanafunzi chini ya comfortable-- au kuthubutu kusema mdogo comfortable-- kwa ajili ya nani 745 00:35:39,630 --> 00:35:41,869 masaa ya ofisi ni si mazingira zaidi kuwalea 746 00:35:41,869 --> 00:35:43,660 na ni hakika si zaidi stress-bure. 747 00:35:43,660 --> 00:35:47,430 Hasa wakati uliopangwa ni kubwa, sisi proactively jozi ninyi wenyewe 748 00:35:47,430 --> 00:35:51,440 na mwanachama wa wafanyakazi kufanya kazi na juu ya baadhi ya ratiba ya mara kwa mara kama mahitaji yako 749 00:35:51,440 --> 00:35:53,850 na ratiba yao inaruhusu. 750 00:35:53,850 --> 00:35:55,260 >> Na wafanyakazi. 751 00:35:55,260 --> 00:36:01,020 Naomba kuanzisha Davon, Rob, na Gabriel, wakuu wa mwaka huu. 752 00:36:01,020 --> 00:36:02,370 Ukitaka kila kama say-- 753 00:36:02,370 --> 00:36:03,349 >> [Makofi] 754 00:36:03,349 --> 00:36:03,849 --a neno. 755 00:36:03,849 --> 00:36:05,328 [Makofi] 756 00:36:05,328 --> 00:36:10,270 757 00:36:10,270 --> 00:36:13,220 Davon juu ya hapa ni meneja bila shaka, ambayo 758 00:36:13,220 --> 00:36:15,730 ina maana katika jukumu lake ya muda yeye husaidia kwa utekelezaji 759 00:36:15,730 --> 00:36:18,424 na vifaa ya CS50. 760 00:36:18,424 --> 00:36:19,340 DAVON: Yeah, hi, guys. 761 00:36:19,340 --> 00:36:20,965 Utaona mengi na mimi wakati wa masaa ya ofisi. 762 00:36:20,965 --> 00:36:22,110 Mimi itabidi kufundisha sehemu. 763 00:36:22,110 --> 00:36:25,150 Na kama wewe risasi barua pepe mbele, Mimi pengine utasikia kuwa kujibu. 764 00:36:25,150 --> 00:36:27,670 Hivyo mimi itabidi kuona kura ya wewe wote muhula. 765 00:36:27,670 --> 00:36:29,890 Na kuwakaribisha kwa CS50. 766 00:36:29,890 --> 00:36:38,330 >> DAVID J. Malan: Na sasa Gabriel, ambaye mwenyewe alikuwa tu freshman mwaka jana, 767 00:36:38,330 --> 00:36:41,820 lakini kwa kipindi cha miaka michache ina imekuwa kazi toleo yake mwenyewe ya CS50 768 00:36:41,820 --> 00:36:44,660 katika Brazil, ambapo yeye kupakuliwa wote wa content-- shaka ya 769 00:36:44,660 --> 00:36:46,890 ambayo ni wazi kuwa zingine na kuwekwa online-- 770 00:36:46,890 --> 00:36:51,480 ili aweze kutafsiri kwa Ureno na kisha kufundisha zaidi ya 100 771 00:36:51,480 --> 00:36:54,610 wa wanafunzi wake juu ya mwendo wa miaka michache, 772 00:36:54,610 --> 00:36:57,650 akifundisha katika lugha yake ya asili mtaala bila shaka ya. 773 00:36:57,650 --> 00:36:58,964 >> GABRIEL: Hello. 774 00:36:58,964 --> 00:37:00,912 >> [Makofi] 775 00:37:00,912 --> 00:37:06,669 776 00:37:06,669 --> 00:37:07,710 GABRIEL: Hi, mimi nina Gabriel. 777 00:37:07,710 --> 00:37:09,340 Mimi nina kichwa TF bila shaka. 778 00:37:09,340 --> 00:37:10,780 Na I hope itabidi upendo CS50. 779 00:37:10,780 --> 00:37:12,830 Hii ni CS50. 780 00:37:12,830 --> 00:37:14,697 >> DAVID J. Malan: Sasa kwa Rob. 781 00:37:14,697 --> 00:37:15,780 Oh, unataka kuanzishwa? 782 00:37:15,780 --> 00:37:16,696 >> Rob: Hapana, mimi sijui. 783 00:37:16,696 --> 00:37:18,225 [Kicheko] 784 00:37:18,225 --> 00:37:19,475 DAVID J. Malan: Na Rob Boden. 785 00:37:19,475 --> 00:37:22,300 [Kicheko] 786 00:37:22,300 --> 00:37:23,800 Rob: Hi, mimi nina Rob. 787 00:37:23,800 --> 00:37:27,220 Huu ni mwaka wa tano yangu wanaohusika na bila shaka. 788 00:37:27,220 --> 00:37:29,220 Kila mwaka, ni tu bora na darasa bora, 789 00:37:29,220 --> 00:37:31,550 hivyo guys ni wazi kwenda kuwa kutisha. 790 00:37:31,550 --> 00:37:33,181 Natumaini wote kuwa na furaha na hayo. 791 00:37:33,181 --> 00:37:34,430 Mimi nina kwenda kuwa na furaha na hayo. 792 00:37:34,430 --> 00:37:36,670 Hivyo kuona wewe kote. 793 00:37:36,670 --> 00:37:38,445 >> DAVID J. Malan: Na wakati si kibali us-- 794 00:37:38,445 --> 00:37:39,670 >> [Makofi] 795 00:37:39,670 --> 00:37:41,661 >> Wakati si kibali us kuanzisha kila mtu 796 00:37:41,661 --> 00:37:44,660 juu ya hatua na wote wa wenzao ambao ni ununuzi madarasa leo. 797 00:37:44,660 --> 00:37:47,390 Lakini naomba kuanzisha Belinda na CS50 Puzzle 798 00:37:47,390 --> 00:37:49,550 Day, ambayo watapata hii kuja Jumamosi, ambayo 799 00:37:49,550 --> 00:37:51,800 ni ya kwanza ya kubwa matukio wadogo bila shaka ya. 800 00:37:51,800 --> 00:37:54,300 >> Hii moja hasa maana nyundo nyumbani uhakika 801 00:37:54,300 --> 00:37:57,580 kwamba sayansi ya kompyuta ni hatimaye si kuhusu programu, lakini badala ya 802 00:37:57,580 --> 00:37:59,280 kuhusu kutatua tatizo zaidi kwa ujumla. 803 00:37:59,280 --> 00:38:01,450 Na Puzzle Day, kama wewe utakuwa kuona, kuleta 804 00:38:01,450 --> 00:38:04,207 na wanafunzi wako together-- sisi matumaini Jumamosi hii. 805 00:38:04,207 --> 00:38:04,961 >> Belinda: OK. 806 00:38:04,961 --> 00:38:05,750 Hi, guys. 807 00:38:05,750 --> 00:38:06,740 Hivyo shukrani. 808 00:38:06,740 --> 00:38:10,120 Hivyo kama nahodha tukufu yetu akasema, jina langu Belinda. 809 00:38:10,120 --> 00:38:12,100 Mimi ni sophomore katika Quincy House. 810 00:38:12,100 --> 00:38:15,730 >> I, tu kama wewe guys, alichukua CS50 mwaka jana, kwa kweli kupendwa hivyo. 811 00:38:15,730 --> 00:38:17,960 Nina doa laini kwa you guys katika safu ya tatu. 812 00:38:17,960 --> 00:38:21,384 Na mimi nina fahari kusema, mimi nina sasa katika uhusiano nia 813 00:38:21,384 --> 00:38:22,300 kwa CS50 [inaudible]. 814 00:38:22,300 --> 00:38:22,799 OK. 815 00:38:22,799 --> 00:38:26,140 Hiyo ilikuwa toleo yangu na kilema cha mzaha. 816 00:38:26,140 --> 00:38:28,320 >> Anyway, hivyo kuhama, nilitaka kukaribisha 817 00:38:28,320 --> 00:38:31,439 nyie wote i-maabara, au HBS mizinga. 818 00:38:31,439 --> 00:38:33,730 Sisi ni kwenda kuwa baada ya Puzzle Day 12:00-03:00. 819 00:38:33,730 --> 00:38:37,680 Na ni nafasi kubwa kwa ajili yenu guys kukutana na rafiki yako wenzake CS, 820 00:38:37,680 --> 00:38:42,780 kutatua baadhi yasiyo ya CS puzzles, kama Kapteni zilizotajwa, na pia kula baadhi ya chakula bure, 821 00:38:42,780 --> 00:38:46,910 kupata baadhi ya zawadi kushangaza, kama zawadi ya kadi, $ 75 kwa mtu, 822 00:38:46,910 --> 00:38:48,400 na also-- ni ipi? 823 00:38:48,400 --> 00:38:49,540 Wii U au kitu? 824 00:38:49,540 --> 00:38:50,333 Wii U? 825 00:38:50,333 --> 00:38:51,040 Ndiyo. 826 00:38:51,040 --> 00:38:52,330 Kwa bahati nasibu yetu. 827 00:38:52,330 --> 00:38:52,830 Kutisha. 828 00:38:52,830 --> 00:38:54,310 Hivyo mimi itabidi fimbo karibu baada ya darasa. 829 00:38:54,310 --> 00:38:56,770 Na kama wewe guys kuwa na yoyote maswali, napenda kujua. 830 00:38:56,770 --> 00:38:59,980 >> DAVID J. Malan: Na utaona, zaidi ya hii kuna kitu cha kufanya leo. 831 00:38:59,980 --> 00:39:01,920 Tatizo la kwanza kuweka kwenda nje ya Ijumaa. 832 00:39:01,920 --> 00:39:05,420 Lakini ili kuleta nyumbani leo, Ningependa kuanzisha wewe hasa moja zaidi 833 00:39:05,420 --> 00:39:09,080 mwanachama wa wafanyakazi, Colton Ogden hapa, ambao mikono yao sasa 834 00:39:09,080 --> 00:39:12,250 ulinzi juu kwa mtawala hii MIDI 835 00:39:12,250 --> 00:39:15,170 nyundo nyumbani uhakika zaidi kwamba sayansi ya kompyuta, pia, 836 00:39:15,170 --> 00:39:19,130 ina applicability mbali zaidi ya uhandisi na STEM na sayansi ya kompyuta yenyewe, 837 00:39:19,130 --> 00:39:22,890 kupanua hata kwenye nyanja kama vile muziki. 838 00:39:22,890 --> 00:39:30,590 >> Colton ina kindly offered-- Nilidhani mmoja wao alikuwa anaenda kurekebisha mwelekeo. 839 00:39:30,590 --> 00:39:34,400 Andrew, kama tunaweza kumwita lengo zaidi ya hapa kwa muda tu. 840 00:39:34,400 --> 00:39:36,780 >> Nini Colton amefanya mapema ni mpango 841 00:39:36,780 --> 00:39:40,345 kifaa hiki, pedi hii ya kifungo kwamba unaweza kuona picha hapa juu, 842 00:39:40,345 --> 00:39:42,470 kama mtawala MIDI, ambapo kila ya kifungo wale 843 00:39:42,470 --> 00:39:47,080 ni wired na hasa kumbuka muziki au sauti, kwa ujumla zaidi kurekodi, 844 00:39:47,080 --> 00:39:50,445 vile kwamba kwa kucheza mifumo ya hizi vifungo, kiasi kama mifumo ya bits, 845 00:39:50,445 --> 00:39:52,620 wanaweza kuwakilisha mengine ngazi ya dhana ya juu. 846 00:39:52,620 --> 00:39:56,750 Je, yeye kuwa na uwezo hatimaye kutupeleka nyumbani hapa leo? 847 00:39:56,750 --> 00:39:59,540 Bila wasiwasi zaidi, kama tunaweza dim taa, 848 00:39:59,540 --> 00:40:03,145 na kurejea kwenye screen nyuma ya Colton. 849 00:40:03,145 --> 00:40:03,865 >> Watazamaji: Woo! 850 00:40:03,865 --> 00:40:06,090 >> DAVID J. Malan: Hii ni CS50. 851 00:40:06,090 --> 00:40:10,518 >> [MUSIC KUCHEZA] 852 00:40:10,518 --> 00:42:46,018 853 00:42:46,018 --> 00:42:49,420 >> [Makofi] 854 00:42:49,420 --> 00:42:54,766 855 00:42:54,766 --> 00:42:56,450 >> Hiyo ni kwa CS50. 856 00:42:56,450 --> 00:42:57,950 Tutaona wewe Ijumaa. 857 00:42:57,950 --> 00:42:59,890 Baadhi ya keki watapata wewe katika transept. 858 00:42:59,890 --> 00:43:04,046 859 00:43:04,046 --> 00:43:08,850 >> [MUSIC KUCHEZA] 860 00:43:08,850 --> 00:45:49,227