1
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>> [Daqq tal-mużika]

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[MUSIC - Rossini, "RANZ DES
VACHES "MINN WILLIAM TELL]

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>> [MUSIC - l-taħbit INGLIŻ, "MARZU
TAL-KAPIJIET iduru "]

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>> [Applause U cheering]

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>> DAVID Malan: Allura dan huwa CS50.

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Jisimni David Malan.

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U 73% tal jkollok ebda esperjenza minn qabel
ma 'xjenza tal-kompjuter,

11
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kuntrarjament għal dak li inti tista 'taħseb.

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Hekk illum ħsibna aħna se ċippa bogħod
f'dak nuqqas ta 'familjarità, iżda wkoll

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jagħtuk sens ta ', għal dawk minnkom
bil-kumdità aktar, li direzzjonijiet

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inti tista 'tmur dan is-semestru.

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>> Mela ejja nibdew ma 'dan.

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I tassew għandek ebda idea x'hemm ġewwa tal
kompjuter, anki jekk, bħal inti, I

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jużawh kuljum.

18
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Iżda huwa xi tip ta 'kaxxa, u hemm
mhux ħafna inputs fis dan.

19
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Minimament, hemm, liema?

20
00:03:01,350 --> 00:03:03,120
Probabbilment korda enerġija.

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>> U tabilħaqq ma dan l-ingredjent wieħed,
elettriku, we jidhru li huma kapaċi

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tagħmel pjuttost ftit dawn il-jiem.

23
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Iżda fl-aħħar tal-ġurnata, aħna
għandha tirrappreżenta l-affarijiet

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li aħna jimpurtahom.

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Irridu jirrapreżentaw l-informazzjoni
f'xi forma.

26
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U int probabilment inqas vagament
familjari mal-idea billi binarju jew

27
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bits b'xi jew oħrajn, kompjuters
jitnaqqas għal żero u dawk.

28
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Iżda nistgħu iħaddnu dan u mill-inqas
tpoġġi daqsxejn ta 'dawl għal dak?

29
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>> So I jkollhom dawn ftit
bozoz mejda hawn.

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Għandi żbokk elettriku hawnhekk.

31
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U jien ser nipproponi li ġewwa
tal-kompjuter tiegħi huwa mill-inqas waħda ta '

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dawn l-affarijiet, xi ħaġa li kapaċi
li jkunu jinxtegħlu jew jintfew.

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F'dan il-każ, huwa tabilħaqq fanal desk,
iżda fl-livell aktar baxx, huwa xi ħaġa

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imsejħa transistor.

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>> Iżda fid-dinja tagħna, huwa fanal desk, hekk
Jien ser jimxi 'l quddiem u plagg dan

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f'elettriku tiegħi hawn.

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U jien jsostnu li jużaw dan sempliċi,
mezz sempliċi, dan is-swiċċ sempliċi, I

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jistgħu jirrapreżentaw l-informazzjoni.

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Per eżempju, id-dritt issa, I am
jirrappreżenta xejn, id-dritt?

40
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Jien jirrappreżentaw dak I ser sejħa 0 jew
falza, l-oppost ta 'xi ħaġa

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attwalment jkunu preżenti.

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Imma jekk I sempliċiment dawwar dan is-swiċċ,
issa stajt rappreżentati '1.

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Hekk billi tuża din il-biċċa sempliċi ħafna ta '
memorja, jekk inti se, I jistgħu jirrappreżentaw

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informazzjoni.

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>> Issa sfortunatament, kompjuter tiegħi
ma tistax tagħmel kollha li ħafna.

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Hija tista 'biss jirrappreżentaw żewġ valuri
fid-dinja kollha -

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0 jew 1.

48
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Imma x'hemm soluzzjoni ovvja, issa,
jekk irridu li jespandu l-kompjuter tagħna

49
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memorja u jirrappreżentaw aktar
minn sempliċiment 0 u 1?

50
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>> Well, ejja grab ftit oħra bħal din.

51
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Ejja grab swiċċ ieħor, ieħor
transistor, madankollu inti tixtieq li

52
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taħseb dwarha.

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Let me imorru quddiem u plagg dan
fis-kompjuter tiegħi ukoll.

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U jien ser jitolbu, issa, li billi
użu daqsxejn aktar elettriku u

55
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tidwir aktar minn dawn swiċċijiet fuq u
off, I jista 'jirrappreżenta aktar bħal

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informazzjoni.

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>> Allura issa dritt, din hija 1.

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Jekk irrid issa jirrappreżentaw
2, I jistgħu jagħmlu dan.

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Imma tipikament, konvenzjoni, kif aħna ser
eventwalment tara, se jkollhom me tagħmel dan.

60
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Allura dan huwa 0, dan huwa 1.

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Dan ikun 2.

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U mhux sorprendenti, dan ikun 3.

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>> Allura f'dan il-mod, xorta, tista
aħna għadd up saħansitra aktar?

64
00:05:02,610 --> 00:05:06,500
Jekk niġi terz bit, terz swiċċ,
x'inhu l-ogħla numru I issa jistgħu

65
00:05:06,500 --> 00:05:09,720
joqgħod sa minn 0?

66
00:05:09,720 --> 00:05:12,020
So 7 jekk jien jibdew f'0, right?

67
00:05:12,020 --> 00:05:15,980
Għaliex jekk ndur id-dawl fuq u
attwalment plug din it-tielet u finali

68
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dawl fil socket elettriku tiegħi hawnhekk,
allura għandi l-abbiltà li jirrappreżentaw

69
00:05:20,090 --> 00:05:24,930
kwalunkwe minn żewġ valuri hawnhekk, żewġ valuri
hawn, żewġ valuri hawn -

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u so I jistgħu jirrappreżentaw 2 darbiet 2 darbiet
2, jew tmien valuri possibbli.

71
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U jekk nibda kontabilità f'0, sabiex
li l-0, 1, 2, 3, 4, 5, 6, 7.

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00:05:36,340 --> 00:05:37,480
>> Allura dan binarja.

73
00:05:37,480 --> 00:05:39,420
Huwa verament huwa sempliċi bħal dik.

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00:05:39,420 --> 00:05:41,930
U I d jargumentaw li dan huwa effettivament
pjuttost familjari għal ħafna

75
00:05:41,930 --> 00:05:43,180
kulħadd f'din il-kamra.

76
00:05:43,180 --> 00:05:45,710
Let me imorru quddiem u tiftaħ
ftit test editur hawn.

77
00:05:45,710 --> 00:05:49,040
>> U inti tista 'recall mill-iskola grad
li kellna affarijiet bħall-mijiet

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post, il-post għexieren,
u dawk post.

79
00:05:51,970 --> 00:05:55,040
U tfakkar li jekk kellek xi dećimali
numru, bħal xi ħaġa każwali

80
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bħal 123, inti essenzjalment
jiktbu li fil-formola

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ta 'dawn it-tliet kolonni.

82
00:06:00,450 --> 00:06:04,070
U għaliex huwa 1, 2, 3 liema
aħna nafu bħala 123?

83
00:06:04,070 --> 00:06:11,220
Ukoll, fil-kolonna fuq ix-xellug, għandna
wieħed 100 flimkien ma 'tnejn 10s, b'tali mod li 120,

84
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plus tliet 1s, b'tali mod li 123.

85
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>> Issa din id-dinja li aħna biss illuminati
huwa eżattament l-istess bħal

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inti kont qed familjari mal għas-snin,
ħlief issa, kolonni tagħna

87
00:06:21,150 --> 00:06:22,060
mhumiex setgħat ta '10.

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Huma qed biss setgħat ta '2.

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00:06:23,780 --> 00:06:27,830
Allura billi dan huwa l-post dawk, dan
se jkun il-post twos, dan huwa

90
00:06:27,830 --> 00:06:29,540
se jkun il-post fours.

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00:06:29,540 --> 00:06:33,260
>> U minħabba I am biss bl-użu l-aktar sempliċi
ta 'mekkaniżmi li jduru affarijiet

92
00:06:33,260 --> 00:06:37,100
fuq u off - elettriku li jirriżultaw
jew elettriku mhuwiex flowing -

93
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I ma pjuttost jkollhom l-istess espressjoni
medda bħall 0 sa disa.

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Aħna ser jżommha sempliċi super
f'din id-dinja tal-kompjuters.

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I biss ikollhom 0 jew 1 -

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00:06:45,060 --> 00:06:47,890
off jew fuq, falza jew vera.

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00:06:47,890 --> 00:06:52,610
>> U hekk dak li jien jirrappreżentaw dritt issa
huwa 1, 1, 1, minħabba li kull wieħed minn dawn

98
00:06:52,610 --> 00:06:54,000
dwal ikun imdawwal.

99
00:06:54,000 --> 00:06:59,600
Ukoll, li tagħti me wieħed 4 plus wieħed 2, sabiex
li għamilhom 6, plus wieħed 1, u li 7.

100
00:06:59,600 --> 00:07:03,450
U ergo ma din is-sekwenza ta 'tliet
bits jirrappreżentaw in-numru 7.

101
00:07:03,450 --> 00:07:06,330
>> Allura dan kollu ħin, ġewwa tal tiegħek
kompjuter, kienu kull numru ta '

102
00:07:06,330 --> 00:07:08,090
transisters, kwalunkwe numru ta 'bits.

103
00:07:08,090 --> 00:07:10,380
Iżda fl-aħħar tal-ġurnata, aħna
jistgħu jirrapreżentaw l-informazzjoni

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00:07:10,380 --> 00:07:12,560
bħala sempliċi bħal dik.

105
00:07:12,560 --> 00:07:16,770
Issa sfortunatament, konna magħduda biss
sa 7 CS50 s'issa, iżda

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00:07:16,770 --> 00:07:18,550
nisperaw nistgħu nagħmlu daqsxejn
aħjar minn dik.

107
00:07:18,550 --> 00:07:19,550
U fil-fatt nistgħu.

108
00:07:19,550 --> 00:07:23,570
>> Ejja ngħidu li aħna bħala bnedmin biss
arbitrarjament iddeċidiet li se nkunu qed

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00:07:23,570 --> 00:07:28,750
li jassoċjaw numri bħall 1 u 2, 3,
4, 5, 6, 7, ma 'ittri speċifiċi ta'

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l-alfabett.

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00:07:29,410 --> 00:07:32,350
U għal raġunijiet storiċi, jien ser
tibda kemmxejn arbitrarju, imma jien

112
00:07:32,350 --> 00:07:36,880
se ngħid, bnedmin, aħna ser
tiddeċiedi bħala standard, globalment, li

113
00:07:36,880 --> 00:07:43,200
65 jirrappreżenta n-numru l-ittra A.
66 se jirrappreżentaw B. Dot, dot, dot.

114
00:07:43,200 --> 00:07:45,140
90 ser jirrapreżentaw il-Z. ittra

115
00:07:45,140 --> 00:07:48,000
>> U ejja nassumu, jekk aħna verament jqajjem xi
ħasbu fis dan, nistgħu toħroġ

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00:07:48,000 --> 00:07:50,860
bin-numri għall-punti exclamation
u zghar ittri, u tabilħaqq,

117
00:07:50,860 --> 00:07:52,710
nies oħra għamlu dan għalina.

118
00:07:52,710 --> 00:07:56,410
Allura issa kellna bits li nistgħu
jirrappreżentaw numri, numri magħhom

119
00:07:56,410 --> 00:08:00,130
nistgħu jirrappreżentaw ittri, u ma '
ittri nistgħu issa tibda jikkomponu

120
00:08:00,130 --> 00:08:02,650
emails u l-karattri istampar
fuq l-iskrin.

121
00:08:02,650 --> 00:08:05,850
>> So let me jistieden, jekk I jistgħu,
tmien voluntiera kuraġġużi -

122
00:08:05,850 --> 00:08:09,200
li ma mind jidhru mhux biss
fuq camera iżda fuq l-internet -

123
00:08:09,200 --> 00:08:13,130
biex toħroġ hawn u jirrappreżentaw tmien bħal
bits, aktar milli dawn it-tliet.

124
00:08:13,130 --> 00:08:14,380
Allura kif madwar wieħed, tnejn?

125
00:08:14,380 --> 00:08:16,290
Kif dwar tliet?

126
00:08:16,290 --> 00:08:20,230
Kif dwar erba 'dawl
blu, ħames fuq l-aħħar?

127
00:08:20,230 --> 00:08:21,250
Dwar xi ħadd minn hawn?

128
00:08:21,250 --> 00:08:25,320
Sitta quddiem, sebgħa quddiem,
u tmienja quddiem, kif ukoll.

129
00:08:25,320 --> 00:08:29,050
>> So I biss hekk ġara li jiġu ppreparati
bil-mazz sħiħ ta 'slips tal-karta.

130
00:08:29,050 --> 00:08:34,150
U fuq dawn il-biċċiet tal-karti huma numri
li jirrappreżenta dak kolonni

131
00:08:34,150 --> 00:08:35,809
inti guys huma ser jirrappreżentaw.

132
00:08:35,809 --> 00:08:36,740
Allura inti se tkun - x'hemm isem tiegħek?

133
00:08:36,740 --> 00:08:37,570
>> STUDENT: Anna Leah.

134
00:08:37,570 --> 00:08:40,370
>> DAVID Malan: Anna Leah, inti
se jkun il-kolonna 128s.

135
00:08:40,370 --> 00:08:41,059
Inti?

136
00:08:41,059 --> 00:08:41,510
>> STUDENT: Chris.

137
00:08:41,510 --> 00:08:43,620
>> DAVID Malan: Chris se
jkun il-kolonna 64s.

138
00:08:43,620 --> 00:08:44,070
Inti?

139
00:08:44,070 --> 00:08:44,540
>> STUDENT: Dan.

140
00:08:44,540 --> 00:08:46,970
>> DAVID Malan: Dan se
jkun il-kolonna 32s.

141
00:08:46,970 --> 00:08:47,470
>> STUDENT: Pramit.

142
00:08:47,470 --> 00:08:49,430
>> DAVID Malan: Pramit se
jkun il-kolonna 16s.

143
00:08:49,430 --> 00:08:50,290
>> STUDENT: Lillian.

144
00:08:50,290 --> 00:08:51,904
>> DAVID Malan: Lillian se tkun l-8S.

145
00:08:51,904 --> 00:08:52,768
>> STUDENT: Jill.

146
00:08:52,768 --> 00:08:55,025
>> DAVID Malan: Jill se
jkun il-kolonna 4s.

147
00:08:55,025 --> 00:08:55,400
>> STUDENT: Mary.

148
00:08:55,400 --> 00:08:57,000
>> DAVID Malan: Mary se jkunu l-2s, u?

149
00:08:57,000 --> 00:08:57,470
>> STUDENT: David.

150
00:08:57,470 --> 00:08:59,220
>> DAVID Malan: David se
jkun il-kolonna 1s.

151
00:08:59,220 --> 00:09:02,030
Hekk jekk inti guys tista 'żżid ftit
quddiem sabiex kulħadd jista 'jara.

152
00:09:02,030 --> 00:09:05,370
What inti guys ma tara hija li fuq il-
lura ta 'dawn slips tal-karta hija

153
00:09:05,370 --> 00:09:09,760
ftit iqarrqu folja li jkunu infurmati dwar l-
struzzjonijiet dawn it-tmien bits biex jew

154
00:09:09,760 --> 00:09:12,380
jgħollu naħa tagħhom jew le
jgħollu naħa tagħhom.

155
00:09:12,380 --> 00:09:14,100
Jekk idejn tagħhom tmur up, dawn qed
jirrappreżentaw 1.

156
00:09:14,100 --> 00:09:17,120
Jekk idejn tagħhom soġġorni isfel, dawn qed
jirrappreżentaw 0.

157
00:09:17,120 --> 00:09:21,410
>> Sadanittant, aħna l-udjenza għandha tkun
kapaċi biex insemmu, ibbażata fuq dan

158
00:09:21,410 --> 00:09:26,490
mapping, liema tliet ittri kelma dawn
folks wasalt biex tispjega.

159
00:09:26,490 --> 00:09:29,700
Għalhekk fl ftit mument, int ser
aqra l-ewwel linja off-dahar ta '

160
00:09:29,700 --> 00:09:32,880
tiegħek iqarrqu folja, u int jew
ser jgħollu jew le jgħollu naħa tiegħek.

161
00:09:32,880 --> 00:09:35,710
Jekk int 1, inti tqajjem, jekk
int 0, inti toqgħod hemm

162
00:09:35,710 --> 00:09:38,594
awkwardly, biss bħal dik.

163
00:09:38,594 --> 00:09:40,386
Mur.

164
00:09:40,386 --> 00:09:43,945
Dak in-numru, l-ewwel u qabel kollox,
huma jirrappreżentaw dawn guys?

165
00:09:43,945 --> 00:09:47,140

166
00:09:47,140 --> 00:09:48,860
>> 66.

167
00:09:48,860 --> 00:09:49,560
66, id-dritt?

168
00:09:49,560 --> 00:09:52,400
Għandna 1 fil-kolonna 64s,
ta '1 fil-kolonna 2s.

169
00:09:52,400 --> 00:09:56,340
Li tagħti me 66, b'tali mod li jidher
li jirrappreżenta B. So

170
00:09:56,340 --> 00:09:57,075
inti guys jkunu spjegati -

171
00:09:57,075 --> 00:09:58,300
OK, li l-biżżejjed.

172
00:09:58,300 --> 00:09:59,430
B.

173
00:09:59,430 --> 00:10:01,610
>> Allura issa ejja jimxu fuq
tieni ittra tagħna.

174
00:10:01,610 --> 00:10:03,530
Mur.

175
00:10:03,530 --> 00:10:06,860
Min hu aktar mgħaġġel fil matematika hawn?

176
00:10:06,860 --> 00:10:07,750
So 79.

177
00:10:07,750 --> 00:10:11,840
Għal darb'oħra, jekk aħna żid up kollha tal-kolonni
fejn hemm 1, bħalissa, biss

178
00:10:11,840 --> 00:10:14,840
bħal għamilna qabel ma l-aktar sempliċi
ta 'eżempji ta' 7, aħna issa

179
00:10:14,840 --> 00:10:16,140
jiksbu n-numru 79.

180
00:10:16,140 --> 00:10:19,910
Li skond mapping tagħna huwa l-
ittra O. Allura aħna qed kważi hemm.

181
00:10:19,910 --> 00:10:22,590
B, O. U fl-aħħarnett, mur.

182
00:10:22,590 --> 00:10:26,420

183
00:10:26,420 --> 00:10:30,120
>> Liema huma jirrappreżentaw issa?

184
00:10:30,120 --> 00:10:31,370
Kunsens inqas.

185
00:10:31,370 --> 00:10:34,660

186
00:10:34,660 --> 00:10:36,460
C'est biss ħsejjes assoluta.

187
00:10:36,460 --> 00:10:40,090
Iva, huwa fil-fatt 87.

188
00:10:40,090 --> 00:10:40,490
Tajba.

189
00:10:40,490 --> 00:10:44,480
>> Allura jekk aħna issa mappa li back up għal - ejja
tibda sejħa chart ASCII tagħna,

190
00:10:44,480 --> 00:10:46,450
American Standard Kodiċi għall
Interchange informazzjoni.

191
00:10:46,450 --> 00:10:47,700
Li jagħtina l-ittra -

192
00:10:47,700 --> 00:10:51,260

193
00:10:51,260 --> 00:10:54,810
mhux "bo" iżda "pruwa." U li l-perfetta
bekkata li twassal għall inti guys li tieħu pruwa

194
00:10:54,810 --> 00:10:56,100
u ras fuq dahar.

195
00:10:56,100 --> 00:10:56,980
Grazzi ħafna.

196
00:10:56,980 --> 00:10:57,886
>> [Applause]

197
00:10:57,886 --> 00:10:59,136
>> DAVID Malan: Tista 'żżomm minnhom.

198
00:10:59,136 --> 00:11:01,850

199
00:11:01,850 --> 00:11:05,942
Għalkemm attwalment, kieku xi ħadd
bħal fanal desk, ukoll?

200
00:11:05,942 --> 00:11:07,300
>> [Hoot MILL UDJENZA]

201
00:11:07,300 --> 00:11:08,390
>> DAVID Malan: lampa Desk?

202
00:11:08,390 --> 00:11:10,850
>> [Daħk]

203
00:11:10,850 --> 00:11:11,860
>> DAVID Malan: Really?

204
00:11:11,860 --> 00:11:13,230
Bozoz mejda għal kulħadd?

205
00:11:13,230 --> 00:11:14,310
Kull dritt.

206
00:11:14,310 --> 00:11:20,990
Allura jibda bl-aktar sempliċi ħafna ta '
prinċipji, konna issa magħduda mhux biss

207
00:11:20,990 --> 00:11:24,750
up minn 0 it-triq kollha sa 7, konna
jassumi li biss billi jitfa aktar

208
00:11:24,750 --> 00:11:28,080
bits jew aktar dwal jew iktar transisters
fil din il-problema, nistgħu

209
00:11:28,080 --> 00:11:32,680
jirrappreżentaw numri akbar u akbar, u
Ergo, firxiet akbar u akbar ta '

210
00:11:32,680 --> 00:11:33,780
alfabeti, bħall-Ingliż.

211
00:11:33,780 --> 00:11:37,770
U biss ejja tagħti fuq il-fidi għal-lum
li bl-istess mod jistgħu nibdew

212
00:11:37,770 --> 00:11:42,220
jirrappreżentaw grafika u vidjo u kwalunkwe
numru ta 'mezzi oħra li aħna qed

213
00:11:42,220 --> 00:11:43,610
illum familjari.

214
00:11:43,610 --> 00:11:49,240
>> Allura dan huwa CS50, u f'din il-klassi
flimkien minnkom huma, għal darb'oħra, ħafna ħafna

215
00:11:49,240 --> 00:11:53,050
klassi li jkollhom mill-inqas
esperjenza kif inti.

216
00:11:53,050 --> 00:11:57,730
U nsemmi dan biss minħabba pjuttost
spiss, inkluż reċentement bħala wieħed mill

217
00:11:57,730 --> 00:12:01,860
il-freshman pariri avvenimenti u fl
sophomore rebbiegħa li għaddiet li jagħtu pariri

218
00:12:01,860 --> 00:12:06,420
każ, spiss nisimgħu istudenti jiċħadx
meta jkunu ġejjin sal-mejda CS, ukoll,

219
00:12:06,420 --> 00:12:10,070
Stajt ġiet ħsieb dwar it-teħid dan
klassi intro, imma jien ma verament

220
00:12:10,070 --> 00:12:11,120
persuna kompjuter.

221
00:12:11,120 --> 00:12:13,220
Or, imma kulħadd żgur
jaf aktar minn lili.

222
00:12:13,220 --> 00:12:17,340
U nressaq dan fil-akbar font
possibbli, biex twassal dan il-messaġġ li

223
00:12:17,340 --> 00:12:18,730
li mhux fil-fatt il-każ.

224
00:12:18,730 --> 00:12:21,100
>> U jekk int mintix, jekk
I, fil-fatt, jkun hawn?

225
00:12:21,100 --> 00:12:25,950
Tirrealizza li mhux biss dan huwa kors ta
titolu Introduzzjoni għall Computer

226
00:12:25,950 --> 00:12:31,740
Xjenza, huwa Introduzzjoni għall Computer
Xjenza I. Għalhekk hemm tabilħaqq

227
00:12:31,740 --> 00:12:33,170
introduzzjoni tieni tali.

228
00:12:33,170 --> 00:12:35,390
Allura int mhux, fil-fatt,
fil-post żbaljat.

229
00:12:35,390 --> 00:12:39,000
U fost l-għanijiet I jkollhom għal-lum huma
li tikkalma xi tħassib inti

230
00:12:39,000 --> 00:12:42,430
jista 'jkollhom, iżda wkoll żebgħa
stampa ta 'x'hemm fil-maħżen għal

231
00:12:42,430 --> 00:12:45,720
studenti inqas u aktar komdi
bl-istess mod f'dan il-kors.

232
00:12:45,720 --> 00:12:49,320
>> Iżda l-ewwel, kelma fuq waħda mill-għotjiet
għandek illum, fosthom

233
00:12:49,320 --> 00:12:50,780
huma numru ta 'FAQs.

234
00:12:50,780 --> 00:12:54,290
Huwa kien viżjoni ta 'tagħna għal xi żmien
issa li tintroduċi ġdid ta 'gradazzjoni

235
00:12:54,290 --> 00:12:57,010
għażla fis dan il-kors -
jiġifieri, SAT / insodisfaċenti.

236
00:12:57,010 --> 00:13:01,930
Philosophically għalija, huwa ħafna ħafna,
ferm aktar importanti li l-

237
00:13:01,930 --> 00:13:05,050
studenti f'din il-klassi jimpenjaw ruħhom mal-
materjal, jiġu kkontestati mill-

238
00:13:05,050 --> 00:13:09,800
materjal, u tinkwetax ħafna, ferm inqas dwar
il-mekkaniżmi ta punteġġi attwali

239
00:13:09,800 --> 00:13:12,590
u gradi ittra AT semestru
aħħar, iżda verament iħaddnu l-

240
00:13:12,590 --> 00:13:13,970
kors u materjali tagħha.

241
00:13:13,970 --> 00:13:18,140
U tassew dan iħoss, b'mod aktar ġenerali,
għall x'hemm interessanti għalihom, li

242
00:13:18,140 --> 00:13:21,390
jħossu ikkontestata u ppremjati iżda
mingħajr biża ta 'falliment.

243
00:13:21,390 --> 00:13:25,030
>> U fil-fatt, dan ukoll huwa rikorrenti
tema f'dan u oħra tal-bidu

244
00:13:25,030 --> 00:13:28,680
korsijiet f'oqsma oħra, li għandek
dan trepidation meta niġu għall-

245
00:13:28,680 --> 00:13:31,040
tqegħid sieq waħda fil
ilmijiet mhux familjari.

246
00:13:31,040 --> 00:13:34,880
I myself, lura fl-1995,
kien freshman.

247
00:13:34,880 --> 00:13:37,990
I kien ħafna iffukat fuq li
a konċentratur Gov hawn.

248
00:13:37,990 --> 00:13:41,060
And yet I d dejjem kibret bi ftit
ta 'interess fix-xjenza tal-kompjuter.

249
00:13:41,060 --> 00:13:42,180
I kien dejjem kurjużi.

250
00:13:42,180 --> 00:13:47,610
>> Iżda lura mbagħad, anke, kelli din il-biża ta '
anki titjib marda fil CS50, tant

251
00:13:47,610 --> 00:13:49,420
I hekk li lanqas biss shop
it sena freshman.

252
00:13:49,420 --> 00:13:53,460
U l-unika raġuni nressaq marda fil-
sena sophomore bieb kien minħabba I

253
00:13:53,460 --> 00:13:55,340
kienet permessa li tieħu suċċess / falliment.

254
00:13:55,340 --> 00:13:58,920
Iżda anke suċċess / falliment meħtieġ li niġi
l-nerv li jagħmlu appuntament

255
00:13:58,920 --> 00:14:01,970
mal-Professur Kernehan fil-ħin,
iġibu din il-folja kbira ta 'karta, u jistaqsi

256
00:14:01,970 --> 00:14:04,470
lilu għall-firma tiegħu u tiegħu
permess biex tesplora

257
00:14:04,470 --> 00:14:05,700
dawn l-ilmijiet mhux familjari.

258
00:14:05,700 --> 00:14:09,030
>> U ma għen fl-aħħar snin
li meta tagħmel dan fil CS50, meta aħna

259
00:14:09,030 --> 00:14:12,500
użati biex ikunu suċċess / falliment, bl-istess mod kieku
għexieren jew mijiet ta 'klassi tiegħek

260
00:14:12,500 --> 00:14:15,970
ikollok toħroġ, Alla jipprojbixxu, fuq it-
quddiem ta 'Sanders ma' din il-formola, li

261
00:14:15,970 --> 00:14:19,520
f'xi imħuħ jirrappreżenta inkapaċità,
I DARE ngħid, biex iwettqu

262
00:14:19,520 --> 00:14:20,800
huma livell sħabhom ".

263
00:14:20,800 --> 00:14:23,410
Li huwa ħaġa redikola, iżda I do think
hemm dak mentalità.

264
00:14:23,410 --> 00:14:27,210
U hemm qatt ma kien f'din il-kultura
ta 'SAT / insodisfaċenti, jew suċċess / falliment aktar

265
00:14:27,210 --> 00:14:30,610
ġeneralment, f'dan il-kors,
jew verament fuq dan il-kampus.

266
00:14:30,610 --> 00:14:32,310
>> Allura din is-sena aħna mibdula li.

267
00:14:32,310 --> 00:14:35,630
Inkun nofs ecstatic ta
din il-klassi jew aktar ntemmet

268
00:14:35,630 --> 00:14:38,700
bidu CS50 Sib / insodisfaċenti.

269
00:14:38,700 --> 00:14:42,130
Fi żmien sena, ikun isbaħ
jekk kważi kulħadd huwa.

270
00:14:42,130 --> 00:14:44,410
Wara forsi aħna ser jaħdmu
fuq il-gradi ittra fil-Harvard

271
00:14:44,410 --> 00:14:45,480
Kulleġġ aktar ġenerali.

272
00:14:45,480 --> 00:14:48,900
Iżda għal issa, aħna ser nagħmlu dan fi tagħna
isfera stess, u nixtieq heartily

273
00:14:48,900 --> 00:14:53,400
ninkoraġġukom biex tirrevedi dawk FAQs u
jistaqsu mistoqsijiet kif tara xieraq, sabiex

274
00:14:53,400 --> 00:14:58,000
nisperaw li int, b'differenza me, se pjuttost mhux
jkollhom l-istess fattur ta 'biża meta

275
00:14:58,000 --> 00:15:01,040
esplorazzjoni dak li probabbilment
post familjari.

276
00:15:01,040 --> 00:15:02,786
>> Allura dak li huwa CS50?

277
00:15:02,786 --> 00:15:06,150
Huwa introduzzjoni għall-
intrapriżi intellettwali tal-kompjuter

278
00:15:06,150 --> 00:15:07,700
xjenza u l-arti tal-programmazzjoni.

279
00:15:07,700 --> 00:15:08,770
Imma dak li verament ma jfisser?

280
00:15:08,770 --> 00:15:12,510
>> Well, s'issa, tkellimna ħafna fil-qosor
dwar jirrappreżentaw informazzjoni.

281
00:15:12,510 --> 00:15:15,070
Iżda jissoponi li aħna fil-fatt tixtieq
li tagħmel xi ħaġa magħha.

282
00:15:15,070 --> 00:15:17,890
Għandna bżonn li jintroduċu l-kunċett ta '
dak li aħna ser sejħa algoritmu.

283
00:15:17,890 --> 00:15:21,540
Algoriżmu huwa proċedura, proċess,
sett ta 'struzzjonijiet għall-

284
00:15:21,540 --> 00:15:22,780
tagħmel xi ħaġa.

285
00:15:22,780 --> 00:15:25,620
>> U algoritmu tista 'tkun xi ħaġa
sempliċi super.

286
00:15:25,620 --> 00:15:28,660
Per eżempju, eżempju li ma 'xi
minnkom jista 'jkun familjari huwa dan

287
00:15:28,660 --> 00:15:29,350
ħaġa hawn.

288
00:15:29,350 --> 00:15:32,510
Allura dan il-ktieb hawnhekk huwa dejjem aktar
datat, iżda li ladarba fuq żmien, dan

289
00:15:32,510 --> 00:15:34,720
jinsabu lott kollu ta 'ismijiet
u n-numri tat-telefon.

290
00:15:34,720 --> 00:15:37,710
U fil-fatt, jekk jien ridt li ssib
xi ħadd f'dan il-ktieb tat-telefon -

291
00:15:37,710 --> 00:15:39,800
jiġifieri, xi ħadd jismu Mike Smith -

292
00:15:39,800 --> 00:15:43,810
I jista 'jsib Mike Smith fi kwalunkwe numru
ta 'modi pjuttost sempliċi.

293
00:15:43,810 --> 00:15:47,700
I tista 'tibda fil-bidu u
jimxu fuq paġna 1, ma jkunx hemm.

294
00:15:47,700 --> 00:15:49,240
Page 2, ma jkunx hemm.

295
00:15:49,240 --> 00:15:49,960
Page 3.

296
00:15:49,960 --> 00:15:53,430
Hija din l-algorithm huwa li
proċess, korretta?

297
00:15:53,430 --> 00:15:54,620
>> Għalhekk huwa korrett, id-dritt?

298
00:15:54,620 --> 00:15:58,070
Jien tip ta 'idjota biex isir dan fil
il-mod, iżda eventwalment I se

299
00:15:58,070 --> 00:16:02,670
isibu l-kunjom S, u nisperaw Mike
huwa f'dik is-sezzjoni, u jien se jsiru

300
00:16:02,670 --> 00:16:04,100
jsir ma algoritmu tiegħi.

301
00:16:04,100 --> 00:16:05,440
Iżda żgur mhuwiex intuwittivi.

302
00:16:05,440 --> 00:16:08,020
Aktar minn darba kull bniedem raġonevoli f'dan
kamra ma kien jagħmel dan.

303
00:16:08,020 --> 00:16:10,180
What would you għamlu?

304
00:16:10,180 --> 00:16:11,480
>> Youd mxew dritta
għall-nofs, id-dritt?

305
00:16:11,480 --> 00:16:12,000
Bejn wieħed u ieħor l-nofs.

306
00:16:12,000 --> 00:16:16,310
U inti tirrealizza, oh, dawn huma l-Ms
Allura Mike Smith, isem l-aħħar tkun Smith,

307
00:16:16,310 --> 00:16:19,050
mhuwiex, b'mod ċar, allura fil-
nofs tax-xellug tal-ktieb.

308
00:16:19,050 --> 00:16:21,040
Huwa għandu jkun lejn l-
S huwa fid-dritt.

309
00:16:21,040 --> 00:16:24,090
U f'dan il-punt, għalkemm ħafna minna
ma tagħmel dan fir-realtà, nistgħu

310
00:16:24,090 --> 00:16:27,125
litteralment tiċrita din il-problema fil nofs.

311
00:16:27,125 --> 00:16:27,640
>> [Cheering U applause]

312
00:16:27,640 --> 00:16:28,950
>> DAVID Malan: Grazzi.

313
00:16:28,950 --> 00:16:30,150
>> [Cheering U applause]

314
00:16:30,150 --> 00:16:34,660
>> DAVID Malan: Tista 'litteralment tiċrita dan
problema fil nofs, li jħallu lili ma,

315
00:16:34,660 --> 00:16:36,120
litteralment, problema nofs bħala kbar.

316
00:16:36,120 --> 00:16:39,750
Mela jekk dan il-ktieb tat-telefon kien - u
probabbilment kien - madwar 1,000 paġni, issa

317
00:16:39,750 --> 00:16:40,840
huwa biss 500.

318
00:16:40,840 --> 00:16:44,710
Jekk nagħmel dan mill-ġdid u I realizzata, oh,
kkritikat, I marru wisq, jien fil-Ts

319
00:16:44,710 --> 00:16:46,480
taqsima, I tista simili -

320
00:16:46,480 --> 00:16:48,030
figurattivament jew litteralment -

321
00:16:48,030 --> 00:16:50,260
RIP il-ktieb tat-telefon - kien fil-fatt
ħafna aktar faċli dak iż-żmien.

322
00:16:50,260 --> 00:16:53,610
I jistgħu litteralment RIP il-ktieb tat-telefon
fil nofs, li jħallu me issa ma

323
00:16:53,610 --> 00:16:55,186
ma 1,000, ma 500 -

324
00:16:55,186 --> 00:16:56,680
250 paġni.

325
00:16:56,680 --> 00:17:00,210
U I tista 'tmur 125, u nofs ta' dak, u
nofs ta 'dak, u nofs ta' dak,

326
00:17:00,210 --> 00:17:04,760
sakemm finalment I ser jitħalla bi
wieħed biss paġna waħda.

327
00:17:04,760 --> 00:17:06,430
>> [Daħk]

328
00:17:06,430 --> 00:17:07,589
>> DAVID Malan: Dik hija l-
parti I tonqos fuq.

329
00:17:07,589 --> 00:17:10,400
Paġna waħda waħda li fiha tkun
Mike nisperaw huwa.

330
00:17:10,400 --> 00:17:14,630
Issa dawk algoritmi differenti jistgħu jkunu
tip ta stmata jew evalwat

331
00:17:14,630 --> 00:17:15,270
modi differenti.

332
00:17:15,270 --> 00:17:17,300
L-ewwel wieħed kien ħafna lineari, right?

333
00:17:17,300 --> 00:17:18,500
Dawwar il-paġna, tfittex Mike.

334
00:17:18,500 --> 00:17:19,630
Dawwar il-paġna, tfittex Mike.

335
00:17:19,630 --> 00:17:20,560
Huwa ħafna lineari.

336
00:17:20,560 --> 00:17:23,339
Jekk hemm wieħed page aktar fil-telefon
ktieb, huwa probabbilment se jieħu me

337
00:17:23,339 --> 00:17:27,380
wieħed aktar sekonda, unità waħda oħra ta 'żmien,
iżda aħna qed komputazzjoni żmien.

338
00:17:27,380 --> 00:17:32,470
>> So I jista 'jiġbed bħal dan din il-linja
hawn, fejn id-daqs tal-

339
00:17:32,470 --> 00:17:34,700
żidiet problema mix-xellug għal-lemin -

340
00:17:34,700 --> 00:17:37,480
ktieb tat-telefon gets iżgħar biex tikber -

341
00:17:37,480 --> 00:17:41,080
u l-ħin se tiżdied fuq
l-assi vertikali, l-akbar

342
00:17:41,080 --> 00:17:42,030
il-ktieb tat-telefon huwa.

343
00:17:42,030 --> 00:17:46,180
Allura n huwa biss varjabbli ġenerali li
xjenzjati tal-kompjuter tuża biex jirrappreżentaw

344
00:17:46,180 --> 00:17:48,210
xi valur, xi numru.

345
00:17:48,210 --> 00:17:50,740
Allura n hija ser iżżid b'mod lineari.

346
00:17:50,740 --> 00:17:53,040
Doppju tad-daqs tal-ktieb tat-telefon, huwa
ser tieħu me doppju

347
00:17:53,040 --> 00:17:54,780
żmien, x'aktarx, biex isibu Mike.

348
00:17:54,780 --> 00:17:56,390
>> Now I seta 'kien intelliġenti
dwar dan, id-dritt?

349
00:17:56,390 --> 00:17:57,800
I kien jkollna bored malajr.

350
00:17:57,800 --> 00:17:58,910
Seta 'jsir dan billi twos.

351
00:17:58,910 --> 00:18:01,870
Allura żewġ paġni, imbagħad erba,
imbagħad sitt, imbagħad tmienja.

352
00:18:01,870 --> 00:18:05,220
U I tista 'tibda jtajru permezz ta' dan ta '
ftit aktar mgħaġġel, għalkemm riskju minuri ta '

353
00:18:05,220 --> 00:18:09,210
qbiż Mike, iżda li kurva mhuwiex
se jkun dak kollu li differenti.

354
00:18:09,210 --> 00:18:12,550
Huwa għadu għaddej biex tkun dritta
linja, iżda ftit aktar mgħaġġel.

355
00:18:12,550 --> 00:18:13,710
>> Imma dak li ma nagħmel?

356
00:18:13,710 --> 00:18:15,845
I attwalment ma xi ħaġa
fundamentalment aħjar.

357
00:18:15,845 --> 00:18:21,990
I jintlaħaq dak li aħna ser sejħa logaritmika
ħin, log tat n, fejn dan aħdar

358
00:18:21,990 --> 00:18:27,730
linja għandha ħafna, ħafna, ħafna
tarf inqas dritti għal dan.

359
00:18:27,730 --> 00:18:33,050
U pjuttost, jissuġġerixxi, kif sort ta '
approċċi infinity dejjem hekk bil-mod,

360
00:18:33,050 --> 00:18:36,700
li I jistgħu attwalment tieħu 1,000 paġna
ktieb tat-telefon, double-daqs tagħha

361
00:18:36,700 --> 00:18:39,610
sena d-dieħla - għaliex jissoponi ħafna
aktar nies jersqu lejn belt.

362
00:18:39,610 --> 00:18:43,250
>> Allura issa stajt ltqajna 2,000 paġni, imma kif
ħafna aktar passi hija li aktar intelliġenti

363
00:18:43,250 --> 00:18:45,200
algoritmu se tieħu?

364
00:18:45,200 --> 00:18:46,060
Just wieħed.

365
00:18:46,060 --> 00:18:48,060
I mean, li l-ħaġa qawwija.

366
00:18:48,060 --> 00:18:51,400
Jekk immorru 4,000 paġni sena d-dieħla,
li għaddej biex jieħdu me

367
00:18:51,400 --> 00:18:53,020
biss żewġ passi aktar.

368
00:18:53,020 --> 00:18:56,500
Allura inti tista tarmi akbar u akbar
problemi fil lili, ma b'differenza il-web huwa

369
00:18:56,500 --> 00:18:59,560
jitfg problemi akbar u akbar
kull jum fil Googles u facebooks ta

370
00:18:59,560 --> 00:19:01,590
id-dinja, u mhuwiex
tali big deal.

371
00:19:01,590 --> 00:19:05,840
Minħabba I tpoġġi aktar riflessjoni u l-kura fil-
algoritmu tiegħi li ma isolvu

372
00:19:05,840 --> 00:19:07,020
problemi b'mod effiċjenti.

373
00:19:07,020 --> 00:19:09,260
>> U fil-fatt, li se jkun wieħed mill-
l-għanijiet ta 'dan il-kors.

374
00:19:09,260 --> 00:19:11,230
Inti se, tul it-triq,
jitgħallmu kif program.

375
00:19:11,230 --> 00:19:13,360
Inti ser jitgħallmu kif program fl
kwalunkwe numru ta 'lingwi.

376
00:19:13,360 --> 00:19:16,670
Iżda fl-aħħar tal-ġurnata, il-kors huwa
dwar soluzzjoni tal-problemi u jkollna

377
00:19:16,670 --> 00:19:20,490
aħjar fil-soluzzjoni ta 'problemi - u, bħal fil-
F'każijiet bħal dan, soluzzjoni ta 'problemi

378
00:19:20,490 --> 00:19:22,030
b'mod aktar effiċjenti.

379
00:19:22,030 --> 00:19:23,990
>> Issa s'issa, aħna ghamilt dan
pjuttost intuwittivament.

380
00:19:23,990 --> 00:19:27,420
Ejja jintroduċu xi ħaġa pjuttost
pseudocode ġeneriku msejħa.

381
00:19:27,420 --> 00:19:29,150
Allura aħna ser eventwalment jiksbu,
f'dan il-kors, li

382
00:19:29,150 --> 00:19:30,570
ipprogrammar ta 'lingwi differenti.

383
00:19:30,570 --> 00:19:34,280
Imma llum aħna ser tagħmel dan bl-Ingliż bħall-
sintassi, fejn inti biss tip ta 'jgħidu

384
00:19:34,280 --> 00:19:37,330
dak li jfisser, imma int qatt tant
konċiż u inti ma joqogħdu jinkwetaw dwar

385
00:19:37,330 --> 00:19:38,960
grammatika u sentenzi kompluta.

386
00:19:38,960 --> 00:19:41,600
Inti biss tesprimi lilek innifsek bħala
konċiż possibbli.

387
00:19:41,600 --> 00:19:45,400
>> Allura pseudocode hija l-Ingliż bħall-
sintassi li tirrappreżenta

388
00:19:45,400 --> 00:19:46,750
lingwa ta 'programmar.

389
00:19:46,750 --> 00:19:51,170
U lejn dak il-għan, let me jipproponi li
aħna issa mudell il-proċess aħna biss

390
00:19:51,170 --> 00:19:54,990
deskritti ta 'kif jingħaddu xi ftit
differenti, din id-darba tieħu

391
00:19:54,990 --> 00:19:59,040
tħares lejn dan il-video ta 'ħames minuti prodott
mill-ħbieb tagħna fil TED li

392
00:19:59,040 --> 00:20:03,170
jiddefinixxi dak pseudocode huwa, jiddefinixxi liema
ħsieb algorithmic hija, u anke

393
00:20:03,170 --> 00:20:07,030
għalkemm l-eżempju int ser tara
huwa, fil fih innifsu, super sempliċi, huwa

394
00:20:07,030 --> 00:20:09,820
ser tibda biex tagħtina l-mentali
mudell, il-vokabularju, li biex

395
00:20:09,820 --> 00:20:14,588
tagħmel ħafna, ħafna aktar kumplessi
algoritmi pjuttost malajr.

396
00:20:14,588 --> 00:20:15,576
>> [BEGIN daqq video]

397
00:20:15,576 --> 00:20:29,920
>> [Daqq tal-mużika]

398
00:20:29,920 --> 00:20:31,100
>> Narrator: X'hemm algoritmu?

399
00:20:31,100 --> 00:20:34,730
Fix-xjenza tal-kompjuter, algoriżmu huwa
sett ta 'istruzzjonijiet għas-soluzzjoni xi

400
00:20:34,730 --> 00:20:36,620
problema pass pass.

401
00:20:36,620 --> 00:20:39,650
Tipikament, algoritmi huma esegwiti
minn kompjuters, iżda aħna bnedmin ikollhom

402
00:20:39,650 --> 00:20:41,230
algoritmi, kif ukoll.

403
00:20:41,230 --> 00:20:43,290
Per eżempju, kif tista 'tmur
dwar għadd tan-numru

404
00:20:43,290 --> 00:20:44,750
ta 'nies fil-kamra?

405
00:20:44,750 --> 00:20:47,980
Ukoll, jekk int simili me, youd probabilment
punt f'kull persuna, wieħed fi

406
00:20:47,980 --> 00:20:50,120
żmien, u l-għadd up minn 0.

407
00:20:50,120 --> 00:20:52,970
1, 2, 3, 4, u oħrajn.

408
00:20:52,970 --> 00:20:54,140
>> Ukoll, li algoritmu.

409
00:20:54,140 --> 00:20:57,600
Fil-fatt, ejja jippruvaw jesprimu hu
ftit aktar formali pseudocode -

410
00:20:57,600 --> 00:21:00,700
Sintassi Ingliż simili li tixbaħ
lingwa ta 'programmar.

411
00:21:00,700 --> 00:21:02,580
Ħalli N 0 ugwali.

412
00:21:02,580 --> 00:21:06,970
Għal kull persuna fil-kamra, sett
N ugwali għal N plus 1.

413
00:21:06,970 --> 00:21:08,400
>> Kif jinterpretaw dan pseudocode?

414
00:21:08,400 --> 00:21:12,840
Ukoll, linja waħda jiddikjara, biex ngħidu hekk,
varjabbli msejħa N u initializes

415
00:21:12,840 --> 00:21:14,250
valur tiegħu għal 0.

416
00:21:14,250 --> 00:21:17,550
Dan ifisser biss li fil-bidu ta '
algoritmu tagħna, il-ħaġa li

417
00:21:17,550 --> 00:21:19,650
aħna qed isserraħ għandu valur ta '0.

418
00:21:19,650 --> 00:21:22,620
Wara kollox, qabel nibdew għadd,
aħna ma jingħaddux xejn s'issa.

419
00:21:22,620 --> 00:21:25,340
Sejħat dan il-varjabbli N
huwa biss konvenzjoni.

420
00:21:25,340 --> 00:21:26,890
I setgħet hija imsejħa xejn aktar.

421
00:21:26,890 --> 00:21:30,560
>> Issa line żewġ demarks l-bidu ta '
loop, sekwenza ta 'passi li se

422
00:21:30,560 --> 00:21:32,310
jirrepetu xi numru ta 'drabi.

423
00:21:32,310 --> 00:21:35,910
Għalhekk fl-eżempju tagħna, il-pass aħna qed tieħu
qed isserraħ nies fil-kamra.

424
00:21:35,910 --> 00:21:38,730
Taħt linja tnejn huwa tliet linja,
li jiddeskrivi eżattament kif

425
00:21:38,730 --> 00:21:40,160
aħna ser tmur dwar għadd.

426
00:21:40,160 --> 00:21:43,440
Il-indentazzjoni jimplika li huwa
tliet linja li se jirrepetu.

427
00:21:43,440 --> 00:21:47,380
>> Allura dak li l-pseudocode qed tgħid huwa
li wara li jibdew minn 0, għal kull

428
00:21:47,380 --> 00:21:50,690
persuna fil-kamra, aħna ser
tiżdied N-1.

429
00:21:50,690 --> 00:21:53,050
Issa dan huwa algoritmu korretta?

430
00:21:53,050 --> 00:21:54,580
Well, ejja bang fuq hija daqsxejn.

431
00:21:54,580 --> 00:21:57,270
Taħdem jekk ikun hemm
żewġ persuni fil-kamra?

432
00:21:57,270 --> 00:21:58,170
Ejja ara.

433
00:21:58,170 --> 00:22:00,260
>> F'linja waħda, aħna initialize N għal 0.

434
00:22:00,260 --> 00:22:03,660
Għal kull wieħed minn dawn iż-żewġ persuni,
aħna mbagħad inkrement N-1.

435
00:22:03,660 --> 00:22:07,310
Allura fuq l-ewwel vjaġġ permezz tal-
loop, aħna aġġornament N 0-1.

436
00:22:07,310 --> 00:22:11,070
Fuq it-tieni vjaġġ permezz-istess
loop, aħna aġġornament N 1-2.

437
00:22:11,070 --> 00:22:15,780
U hekk sa tmiem dan algoritmu, l n hija 2,
li tabilħaqq jaqbel man-numru ta '

438
00:22:15,780 --> 00:22:16,700
nies fil-kamra.

439
00:22:16,700 --> 00:22:17,760
>> S'issa, hekk tajjeb.

440
00:22:17,760 --> 00:22:19,610
Kif dwar każ kantuniera, għalkemm?

441
00:22:19,610 --> 00:22:22,590
Ejja ngħidu li jeżistu 0 nies
fil-kamra - minbarra me,

442
00:22:22,590 --> 00:22:24,170
min qed jagħmel l-għadd.

443
00:22:24,170 --> 00:22:27,150
F'linja waħda, aħna initialize N għal 0.

444
00:22:27,150 --> 00:22:30,280
Din id-darba, għalkemm, tliet linja ma
tesegwixxi fil-livelli kollha peress li ma hemmx

445
00:22:30,280 --> 00:22:31,370
persuna fil-kamra.

446
00:22:31,370 --> 00:22:35,260
U hekk N tibqa 0, li jaqbel mal-
numru ta 'nies fil-kamra.

447
00:22:35,260 --> 00:22:36,420
Pretty sempliċi, id-dritt?

448
00:22:36,420 --> 00:22:39,630
>> Iżda għadd poplu wieħed fi żmien
huwa pjuttost ineffiċjenti, wisq, no?

449
00:22:39,630 --> 00:22:40,920
Żgur nistgħu nagħmlu aħjar.

450
00:22:40,920 --> 00:22:43,120
Għaliex ma jgħoddux żewġ persuni fi żmien?

451
00:22:43,120 --> 00:22:49,300
Minflok għadd 1, 2, 3, 4, 5, 6, 7,
8, u oħrajn, għaliex ma jgħoddux, 2,

452
00:22:49,300 --> 00:22:51,460
4, 6, 8, u l-bqija?

453
00:22:51,460 --> 00:22:53,700
Huwa anki ħsejjes malajr,
u żgur huwa.

454
00:22:53,700 --> 00:22:56,240
>> Ejja tesprimi din optimization
fil pseudocode.

455
00:22:56,240 --> 00:22:57,800
Ħalli N 0 ugwali.

456
00:22:57,800 --> 00:23:02,450
Għal kull par ta 'nies fil-kamra,
stabbiliti N ugwali għal N plus 2.

457
00:23:02,450 --> 00:23:04,120
Bidla pjuttost sempliċi, id-dritt?

458
00:23:04,120 --> 00:23:06,750
Pjuttost milli għadd poplu wieħed
fi żmien, aħna minflok joqgħod

459
00:23:06,750 --> 00:23:08,300
minnhom tnejn fi żmien.

460
00:23:08,300 --> 00:23:10,980
Dan algoritmu huwa b'hekk doppju
malajr bħala l-aħħar.

461
00:23:10,980 --> 00:23:12,180
>> Imma huwa korrett?

462
00:23:12,180 --> 00:23:12,920
Ejja ara.

463
00:23:12,920 --> 00:23:15,330
Taħdem jekk ikun hemm
żewġ persuni fil-kamra?

464
00:23:15,330 --> 00:23:17,550
F'linja waħda, aħna initialize N għal 0.

465
00:23:17,550 --> 00:23:20,920
Għal dik par wieħed ta 'nies,
aħna mbagħad inkrement N bi tnejn.

466
00:23:20,920 --> 00:23:24,860
U hekk sa tmiem dan algoritmu tal, N huwa 2,
li tabilħaqq jaqbel man-numru ta '

467
00:23:24,860 --> 00:23:25,650
nies fil-kamra.

468
00:23:25,650 --> 00:23:28,250
>> Ejja ngħidu li jmiss li hemm
0 nies fil-kamra.

469
00:23:28,250 --> 00:23:30,840
F'linja waħda, aħna initialize N għal 0.

470
00:23:30,840 --> 00:23:34,330
Bħal qabel, tliet linja ma jeżegwixxix
fil-livelli kollha, peress li ma jkunx hemm xi pari

471
00:23:34,330 --> 00:23:35,380
ta 'nies fil-kamra.

472
00:23:35,380 --> 00:23:38,350
U hekk N tibqa 0, li tabilħaqq
jaqbel man-numru ta '

473
00:23:38,350 --> 00:23:39,570
nies fil-kamra.

474
00:23:39,570 --> 00:23:42,280
>> Imma x'jiġri jekk hemm tliet
nies fil-kamra?

475
00:23:42,280 --> 00:23:44,130
Kif jaħdem dan nol algoritmu?

476
00:23:44,130 --> 00:23:44,990
Ejja ara.

477
00:23:44,990 --> 00:23:47,460
F'linja waħda, aħna initialize N għal 0.

478
00:23:47,460 --> 00:23:50,870
Għal par ta 'dawk in-nies,
aħna mbagħad inkrement N minn 2.

479
00:23:50,870 --> 00:23:51,800
Iżda mbagħad xiex?

480
00:23:51,800 --> 00:23:54,960
M'hemmx par sħiħa ieħor ta 'nies
fil-kamra, hekk linja tnejn ebda

481
00:23:54,960 --> 00:23:56,180
tibqax tapplika.

482
00:23:56,180 --> 00:24:00,530
U hekk sa tmiem dan algoritmu, l N
għadu 2, li mhix korretta.

483
00:24:00,530 --> 00:24:03,810
>> Tabilħaqq, dan algoritmu qal li jkun
buggy, minħabba li għandu żball.

484
00:24:03,810 --> 00:24:05,820
Tikri rimedju ma 'xi pseudocode ġdid.

485
00:24:05,820 --> 00:24:09,670
Ħalli n 0 ugwali għal kull par
ta 'nies fil-kamra.

486
00:24:09,670 --> 00:24:12,550
Set N ugwali għal N plus 2.

487
00:24:12,550 --> 00:24:17,140
Jekk persuna waħda tibqa 'mhux abbinata,
stabbiliti N ugwali għal N plus 1.

488
00:24:17,140 --> 00:24:20,140
Biex issolvi din il-problema partikolari, konna
introdotti, f'konformità erba, a

489
00:24:20,140 --> 00:24:24,520
kundizzjoni, magħrufa bħala fergħa
li tesegwixxi biss jekk hemm waħda

490
00:24:24,520 --> 00:24:26,640
persuna li aħna ma setgħux
par ma 'ieħor.

491
00:24:26,640 --> 00:24:30,440
U hekk issa, jekk hemm waħda jew tlieta
jew kwalunkwe numru fard ta 'nies

492
00:24:30,440 --> 00:24:33,290
il-kamra, dan algoritmu
issa se jgħoddu għalihom.

493
00:24:33,290 --> 00:24:34,560
>> Nistgħu nagħmlu anke aħjar?

494
00:24:34,560 --> 00:24:38,820
Well, nistgħu jgħodd 3s jew 4s jew saħansitra
5s u 10s, iżda lil hinn minn dak, huwa

495
00:24:38,820 --> 00:24:41,360
se tikseb xi ftit
diffiċli għall-punt.

496
00:24:41,360 --> 00:24:44,660
Fl-aħħar tal-ġurnata, kemm jekk issir
minn kompjuters jew bnedmin,

497
00:24:44,660 --> 00:24:46,750
algoritmi huma biss sett
ta 'struzzjonijiet bil-

498
00:24:46,750 --> 00:24:48,290
li sabiex isolvu problemi.

499
00:24:48,290 --> 00:24:49,792
Dawn kienu biss tlieta.

500
00:24:49,792 --> 00:24:52,404
Liema problema kieku inti ssolvi
ma 'algoritmu?

501
00:24:52,404 --> 00:24:52,901
>> [Daqq video END]

502
00:24:52,901 --> 00:24:55,883
>> DAVID Malan: Dan huwa l-ħin biss
I se tidher f'forma cartoons.

503
00:24:55,883 --> 00:25:01,050
Iżda fejn li l-istorja weraq off,
issa, hija kif nistgħu nagħmlu aħjar?

504
00:25:01,050 --> 00:25:04,680
Threes u fours, aħna jsostnu, aħna jista 'joqgħod
nies ħafna aktar mgħaġġla, iżda nistgħu

505
00:25:04,680 --> 00:25:06,290
jagħmlu fundamentalment aħjar minn dik?

506
00:25:06,290 --> 00:25:07,540
And I wager nistgħu.

507
00:25:07,540 --> 00:25:11,980
>> Jekk aħna jintroduċu daqsxejn ta 'tagħna stess
pseudocode hawn, jien ser tipproponi

508
00:25:11,980 --> 00:25:14,550
li nistgħu niksbu linja bħal dan.

509
00:25:14,550 --> 00:25:17,280
Aħna mhux se jgħodd nies
wieħed, tnejn, tlieta, erbgħa.

510
00:25:17,280 --> 00:25:19,470
Aħna mhux se jmorru tnejn,
erba ', sitt, tmienja.

511
00:25:19,470 --> 00:25:23,390
Aħna qed tmur biex tagħmel fundamentalment aħjar
billi terġa 'tifformula l-problema, u f'dan il-

512
00:25:23,390 --> 00:25:27,080
każ, u takkwista inkella
riżorsa sfruttat biżżejjed.

513
00:25:27,080 --> 00:25:31,460
>> Fi ftit mument, I hope inti ser nahfru
u Humer lilna mill-wieqfa fil-

514
00:25:31,460 --> 00:25:34,470
post, f'liema punt aħna qed tmur biex
jsaqsi kull wieħed inti li jidħol għalihom tiegħek

515
00:25:34,470 --> 00:25:36,400
imħuħ in-numru 1.

516
00:25:36,400 --> 00:25:39,560
Inti mbagħad ser dejjem
awkwardly, kif jgħaddi żmien, isibu

517
00:25:39,560 --> 00:25:42,740
xi ħadd ieħor li qed wieqfa, jikkombinaw
numri tiegħek flimkien

518
00:25:42,740 --> 00:25:43,720
billi żżidhom up.

519
00:25:43,720 --> 00:25:47,490
Wieħed minnkom huwa mbagħad se razza biex ipoġġu
isfel ewwel, u l-persuna l-oħra

520
00:25:47,490 --> 00:25:48,880
se jirrepeti.

521
00:25:48,880 --> 00:25:53,090
>> Allura fi kliem ieħor, mill jinżera kollha
inti bin-numru 1, u mbagħad

522
00:25:53,090 --> 00:25:57,800
jikkombinaw dawk 1s fis 2s u dawk 2s
fis 4s, ma 'kulħadd dejjem

523
00:25:57,800 --> 00:26:02,740
bilqiegħda, għandna, fl-aħħar ta '
dan algoritmu, għandhom self waħda biss

524
00:26:02,740 --> 00:26:07,570
ruħ li ma joqogħdu bilqegħda mgħaġġel biżżejjed iżda
li għandha l-għadd udjenzi kollu

525
00:26:07,570 --> 00:26:09,180
f'moħħu tiegħu jew tagħha.

526
00:26:09,180 --> 00:26:13,730
>> Mela jekk inti, ejja imorru quddiem u -
pass wieħed - stand up fil-post.

527
00:26:13,730 --> 00:26:15,600
U tesegwixxi.

528
00:26:15,600 --> 00:26:36,580
>> [Folla murmuring]

529
00:26:36,580 --> 00:26:38,820
>> DAVID Malan: Taf
fejn Lauren hu?

530
00:26:38,820 --> 00:26:40,179
729?

531
00:26:40,179 --> 00:27:23,350
>> [Folla murmuring]

532
00:27:23,350 --> 00:27:24,340
>> DAVID Malan: All right?

533
00:27:24,340 --> 00:27:39,110
>> [Folla murmuring]

534
00:27:39,110 --> 00:27:41,365
>> DAVID Malan: Kull dritt, għandna
jkun joqrob it-tmiem.

535
00:27:41,365 --> 00:27:44,340

536
00:27:44,340 --> 00:27:47,670
Naraw wieħed sħabi wieqfa hawn għadu.

537
00:27:47,670 --> 00:27:48,770
Li inkella jeħtieġ li jiġu paired?

538
00:27:48,770 --> 00:27:50,020
Jekk inti guys tixtieq li par off.

539
00:27:50,020 --> 00:27:53,260

540
00:27:53,260 --> 00:27:56,520
Xi ħadd top up.

541
00:27:56,520 --> 00:27:58,150
Għaliex ma I jagħtu daqqa t'id hawn.

542
00:27:58,150 --> 00:28:01,370
Għall-ftit nies li għadhom
wieqfa, dak numri do you

543
00:28:01,370 --> 00:28:02,790
jkollu f'moħħu tiegħek?

544
00:28:02,790 --> 00:28:04,020
>> STUDENT: 78.

545
00:28:04,020 --> 00:28:06,010
>> DAVID Malan: 78 plus -

546
00:28:06,010 --> 00:28:07,840
Min hu permanenti stabbiliti hawn?

547
00:28:07,840 --> 00:28:08,370
>> STUDENT: 39.

548
00:28:08,370 --> 00:28:09,590
>> DAVID Malan: Plus 39.

549
00:28:09,590 --> 00:28:12,310
Plus li inkella hija għadha wieqfa?

550
00:28:12,310 --> 00:28:13,650
81?

551
00:28:13,650 --> 00:28:15,960
OK, li inkella?

552
00:28:15,960 --> 00:28:17,200
81 Ieħor?

553
00:28:17,200 --> 00:28:17,860
Ara naqra.

554
00:28:17,860 --> 00:28:19,210
U allura x'hemm fid-dahar?

555
00:28:19,210 --> 00:28:20,360
>> STUDENT: 49.

556
00:28:20,360 --> 00:28:21,812
>> DAVID Malan: 49, plus?

557
00:28:21,812 --> 00:28:22,950
>> STUDENT: 98.

558
00:28:22,950 --> 00:28:24,980
>> DAVID Malan: 98 plus?

559
00:28:24,980 --> 00:28:28,190
Hija li xi ħadd ieħor?

560
00:28:28,190 --> 00:28:29,155
12?

561
00:28:29,155 --> 00:28:30,460
Xogħol tajjeb.

562
00:28:30,460 --> 00:28:33,610
>> [Daħk]

563
00:28:33,610 --> 00:28:34,690
>> DAVID Malan: Oh, 112 -

564
00:28:34,690 --> 00:28:35,410
oh.

565
00:28:35,410 --> 00:28:36,220
Xogħol tajjeb!

566
00:28:36,220 --> 00:28:38,660
>> [Daħk]

567
00:28:38,660 --> 00:28:42,570
>> [Applause]

568
00:28:42,570 --> 00:28:43,820
>> DAVID Malan: Ħaddieħor
għadha wieqfa?

569
00:28:43,820 --> 00:28:46,710

570
00:28:46,710 --> 00:28:47,260
Jiddispjacini?

571
00:28:47,260 --> 00:28:48,110
>> STUDENT: 99.

572
00:28:48,110 --> 00:28:49,810
>> DAVID Malan: 99.

573
00:28:49,810 --> 00:28:52,620
Ħaddieħor għadha wieqfa?

574
00:28:52,620 --> 00:28:57,290
U n-numru totali ta 'studenti hawnhekk
huwa attwalment, skond -

575
00:28:57,290 --> 00:28:59,400
għandek numru?

576
00:28:59,400 --> 00:29:03,170
Oh, in-numru attwali ta 'nies fil-
kamra, skond il-konsiderazzjoni li

577
00:29:03,170 --> 00:29:07,660
il fellows tagħlim kienu qed jagħmlu
fit-triq ta 'kulħadd fi, kien 729.

578
00:29:07,660 --> 00:29:11,070
Allura minn roomful ta 'studenti Harvard
li magħduda infushom, il-

579
00:29:11,070 --> 00:29:14,126
tweġiba hija 637.

580
00:29:14,126 --> 00:29:15,480
>> [Daħk]

581
00:29:15,480 --> 00:29:16,350
>> DAVID Malan: So qrib.

582
00:29:16,350 --> 00:29:17,360
Iżda xorta.

583
00:29:17,360 --> 00:29:22,110
OK, b'tali mod li ta 'tagħlim
mument, id-dritt?

584
00:29:22,110 --> 00:29:24,120
Dan issa huwa dak li aħna jiddeskrivu bħala bug.

585
00:29:24,120 --> 00:29:28,120
X'imkien tul it-triq, għamilna xi
aritmetika ħażin, jew xi ħadd poġġa bilqiegħda,

586
00:29:28,120 --> 00:29:29,930
jew xellug, jew xi ħaġa li marret ħażin.

587
00:29:29,930 --> 00:29:30,930
Iżda li l-multa.

588
00:29:30,930 --> 00:29:33,390
Għaliex anki xorta, aħna
ltqajna pjuttost qrib.

589
00:29:33,390 --> 00:29:37,480
U I d jargumentaw li aħna qbilna li l-ħażin
twieġeb ħafna aktar malajr milli I jkollhom

590
00:29:37,480 --> 00:29:39,770
jużaw approċċ aktar lineari tiegħi.

591
00:29:39,770 --> 00:29:42,630
>> Mela ejja nassumu aħna ma fil-fatt tikseb dak
jikkoreġu, iżda naħseb issa dwar dak

592
00:29:42,630 --> 00:29:46,870
kien qed jiġri kull darba, kontra tiegħi
stess algoritmu tipponta naive.

593
00:29:46,870 --> 00:29:48,420
Wieħed, tnejn, tlieta.

594
00:29:48,420 --> 00:29:53,010
Jekk ikun hemm tabilħaqq 729 jew 637 ruħ
hawnhekk, li kien jieħu me

595
00:29:53,010 --> 00:29:57,720
litteralment 637 jew 729 pointings
tal-frotta u

596
00:29:57,720 --> 00:29:59,490
inkrementazzjoni għadd totali tiegħi.

597
00:29:59,490 --> 00:30:01,910
U I jistgħu jagħmlu ftit aħjar minn
għaddejjin f'żewġ, erba ', sitt, tmienja, u

598
00:30:01,910 --> 00:30:05,660
doppju li l-veloċità, forsi anki triplu jew
jikkwadrupla, jiddependi kemm nista '

599
00:30:05,660 --> 00:30:07,110
tagħmel dan jingħaddu my head.

600
00:30:07,110 --> 00:30:10,720
>> Iżda dan l-approċċ li inti guys ħa
kienet fundamentalment differenti.

601
00:30:10,720 --> 00:30:12,770
Minħabba fil-bidu,
kollha inti saqajh.

602
00:30:12,770 --> 00:30:14,620
Allura kull 729.

603
00:30:14,620 --> 00:30:17,370
U mbagħad litteralment nofs
tal inti sib stabbiliti.

604
00:30:17,370 --> 00:30:19,720
U wara dak, oħra
nofs tal inti sib stabbiliti.

605
00:30:19,720 --> 00:30:22,650
U wara dak, oħra
nofs tal inti sib stabbiliti.

606
00:30:22,650 --> 00:30:27,470
>> U n-numru totali ta 'drabi li int
guys setgħet sib stabbiliti hija bejn wieħed u ieħor

607
00:30:27,470 --> 00:30:31,740
tmien jew disa 'jew għaxar darbiet totali,
jiddependi fuq liema għadd totali tagħna huwa.

608
00:30:31,740 --> 00:30:33,300
U nistgħu sort ta 'do
dan il-mod ieħor.

609
00:30:33,300 --> 00:30:37,740
Jekk kellna 1,024 nies fil-kamra, l-
numru totali ta 'drabi inti tista'

610
00:30:37,740 --> 00:30:41,870
tnaqqas bin-nofs 1024 nies huwa 10.

611
00:30:41,870 --> 00:30:43,370
>> Issa taħseb dwarha fl
-direzzjoni oħra.

612
00:30:43,370 --> 00:30:49,170
Ejja ngħidu, ridiculously, li kellna, ngħidu
erba 'biljun ruħ f'din il-kamra,

613
00:30:49,170 --> 00:30:50,860
jew kamra ftit akbar.

614
00:30:50,860 --> 00:30:54,550
Kif ħafna drabi kieku aħna marru
permezz ta 'dan algoritmu, b'tali mod li nofs

615
00:30:54,550 --> 00:30:58,110
ta 'dik il-klassi tiltaqa stabbiliti?

616
00:30:58,110 --> 00:31:03,050
Huwa biss ser jieħdu 32 bħal
operazzjonijiet, anki fi klassi ta 'daqs

617
00:31:03,050 --> 00:31:03,770
erba 'biljun.

618
00:31:03,770 --> 00:31:04,055
Għaliex?

619
00:31:04,055 --> 00:31:06,980
Minħabba erba 'biljun tmur għal żewġ
biljun, tmur għal wieħed miljun, tmur

620
00:31:06,980 --> 00:31:09,925
500 miljun, tmur sa 250
miljun, dot, dot, dot.

621
00:31:09,925 --> 00:31:14,940
I tista 'biss tagħmel dan diviżjoni xi 32
drabi, f'liema punt, kulħadd ħlief

622
00:31:14,940 --> 00:31:17,820
persuna waħda jitħallew wieqfa.

623
00:31:17,820 --> 00:31:21,590
>> U li, wisq, huwa tip ta 'qawwija
idea li dejjem aħna ser nippruvaw

624
00:31:21,590 --> 00:31:24,690
lieva f'dan il-kors, u
ipprogrammar u x-xjenza tal-kompjuter aktar

625
00:31:24,690 --> 00:31:29,400
ġeneralment, dawn il-mikrobi ta 'idea ma
li nistgħu mbagħad isolvu problemi ħafna,

626
00:31:29,400 --> 00:31:31,130
ħafna aktar qawwi.

627
00:31:31,130 --> 00:31:34,610
Allura bdejna pjuttost sempliċi ma 'dak
pseudocode u Guy fil-kamra, imma

628
00:31:34,610 --> 00:31:38,205
issa ma 'kamra kollha sħiħ ta' persuni
Have we jsir fundamentalment aħjar.

629
00:31:38,205 --> 00:31:41,460
>> Well, ejja issa transizzjoni minn
pseudocode għal xi kodiċi attwali.

630
00:31:41,460 --> 00:31:44,200
Din il-lingwa int ser tara jiġri
li għandu jissejjaħ JavaScript, u

631
00:31:44,200 --> 00:31:46,190
aħna ser terġa 'lura għal dan lejn
aħħar semestru tal.

632
00:31:46,190 --> 00:31:49,960
Huwa lingwa ta 'programmar li inti
użu li jagħmlu websajts u oħra bħal

633
00:31:49,960 --> 00:31:51,360
software dawn il-jiem.

634
00:31:51,360 --> 00:31:54,890
U aħna użaw dan, grazzi lil habib
ta 'tagħna fil Stanford, sabiex jikkodifikaw

635
00:31:54,890 --> 00:31:56,630
xi informazzjoni moħbija hawn.

636
00:31:56,630 --> 00:31:59,500
Dan huwa l-arti ta 'steganography,
biex ngħidu hekk, fejn inti tista 'taħbi

637
00:31:59,500 --> 00:32:03,990
informazzjoni fil dak li jidher b'mod ieħor biex
tkun ħoss jew kompletament differenti

638
00:32:03,990 --> 00:32:05,220
image kollox.

639
00:32:05,220 --> 00:32:10,120
Iżda inkorporati f'dan image partikolari
huwa tabilħaqq messaġġ sigriet ta 'tip.

640
00:32:10,120 --> 00:32:12,950
>> So let me go quddiem u iġbed up
l-istess immaġini hawn, dan

641
00:32:12,950 --> 00:32:14,270
żmien fil-web browser.

642
00:32:14,270 --> 00:32:17,710
U jien ser mewġa naħa tiegħi fuq xi wħud
id-dettalji għal-lum, partikolarment

643
00:32:17,710 --> 00:32:21,780
għal dawk minnkom li dan qisu
mhux biss JavaScript iżda Grieg, bħala

644
00:32:21,780 --> 00:32:23,930
kompletament lingwa mhux familjari.

645
00:32:23,930 --> 00:32:26,190
Iżda dan huwa eżempju ta '
lingwa ta 'programmar.

646
00:32:26,190 --> 00:32:30,660
>> U għal issa, jieħdu fuq il-fidi li
dan l-ewwel linja tal-kodiċi -

647
00:32:30,660 --> 00:32:32,470
u skont il-kodiċi, I jfissirx biss test.

648
00:32:32,470 --> 00:32:35,660
Test li I setgħet litteralment ittajpjat
fis-Microsoft Word, jekk kelli l-

649
00:32:35,660 --> 00:32:37,630
software dritt għall mbagħad
tagħmel xi ħaġa magħha.

650
00:32:37,630 --> 00:32:42,120
Source code programmazzjoni, l-ipprogrammar
kodiċi, huwa verament ftit test, u

651
00:32:42,120 --> 00:32:45,420
jistenna differenti bbażata fuq dak lingwa
inti qed tuża, ma b'differenza Ingliż u

652
00:32:45,420 --> 00:32:49,200
Spanjol u Russu kollha ħarsa differenti
meta inti tip lilhom fil-tastiera tiegħek.

653
00:32:49,200 --> 00:32:53,520
>> Allura dan l-ewwel linja, għal issa tieħu
fidi, sempliċiment tiftaħ grafika mill-

654
00:32:53,520 --> 00:32:56,160
internet, li grafika storbjużi
aħna biss raw.

655
00:32:56,160 --> 00:32:59,900
Din il-linja li jmiss hawnhekk huwa eżempju ta '
loop, u aħna fil-fatt raw dak l-istess

656
00:32:59,900 --> 00:33:01,130
jargon fil-video TED.

657
00:33:01,130 --> 00:33:03,750
A loop hija xi ħaġa li jiġri mill-ġdid
u għal darb'oħra, u anki jekk dan

658
00:33:03,750 --> 00:33:08,440
assolutament jistenna cryptic, bl-
keyword għal, u xi parentesi, u

659
00:33:08,440 --> 00:33:09,510
xi semicolons.

660
00:33:09,510 --> 00:33:13,070
Aħna ser terga 'lura għal li qabel twil,
iżda li loop hemm essenzjalment huwa

661
00:33:13,070 --> 00:33:17,310
javżak-programm, iterazzjoni fuq kollha
ta 'dawk tikek storbjużi, mix-xellug għal

662
00:33:17,310 --> 00:33:18,980
dritt, fuq għal isfel.

663
00:33:18,980 --> 00:33:21,260
>> Minħabba fl-aħħar tal-ġurnata, immaġni
bħal dan - u inti tista 'attwalment

664
00:33:21,260 --> 00:33:22,860
tip ta 'tara fuq dan projector -

665
00:33:22,860 --> 00:33:25,280
huwa verament ftit grid ta 'tikek.

666
00:33:25,280 --> 00:33:29,730
Allura nistgħu tidentifika kull waħda minn dawk tikek
minn tikkoordina, x, y, u ma 'dan

667
00:33:29,730 --> 00:33:33,890
programm, issa nistgħu jibdew
tagħmel xi ħaġa għal dawk tikek.

668
00:33:33,890 --> 00:33:37,540
>> Allura dak li jien ser jimxi 'l quddiem hawn u
do huwa jien ser tagħmel xi bidliet.

669
00:33:37,540 --> 00:33:41,000
Ewwel Jien ser imorru quddiem u jeħles
ta 'kollha ta' dak ħadrani u blu

670
00:33:41,000 --> 00:33:43,520
istorbju, u jien ser jimxi 'l quddiem
u t-tip li ġej

671
00:33:43,520 --> 00:33:45,710
ċertament sintassi cryptic.

672
00:33:45,710 --> 00:33:48,020
im għall-immaġni.

673
00:33:48,020 --> 00:33:53,380
stabbiliti blu fil-post x, comma,
post y, għal 0.

674
00:33:53,380 --> 00:33:55,610
Fi kliem ieħor, I jridux biss
itfi kollha tal-blue

675
00:33:55,610 --> 00:33:56,920
tikek li stampa.

676
00:33:56,920 --> 00:33:59,800
>> Jien ser jimxi 'l quddiem issa u kklikkja
dan Mexxi / Save buttuna, u tkun taf

677
00:33:59,800 --> 00:34:02,850
avviż fuq in-naħa tal-lemin,
l-immaġini li tirriżulta jidher.

678
00:34:02,850 --> 00:34:06,120
Issa aħdar super tagħha, iżda li mhux
sorprendenti, minħabba I litteralment daru

679
00:34:06,120 --> 00:34:11,070
off, billi tagħmel 1 ta '0, kollha ta'
l-blu li stampa.

680
00:34:11,070 --> 00:34:12,540
>> Well, issa ejja tagħmel dan daqsxejn aktar.

681
00:34:12,540 --> 00:34:16,989
im għall-immaġni, dot setGreen, x, y.

682
00:34:16,989 --> 00:34:20,659
U dan ifisser biss jtenni mix-xellug
għal-lemin u mbagħad fuq s'isfel.

683
00:34:20,659 --> 00:34:23,520
Dawwar li off b'valur
ta '0, kif ukoll.

684
00:34:23,520 --> 00:34:24,750
Jiffrankaw.

685
00:34:24,750 --> 00:34:28,100
U fuq il-projector, inti ma tistax attwalment
verament tara xejn affattu.

686
00:34:28,100 --> 00:34:31,380
>> Fuq l-iskrin laptop tiegħi, jekk I pari fil biss
il-mod id-dritt, I jista 'jara daqsxejn ta'

687
00:34:31,380 --> 00:34:33,300
immaġni, għaliex dawn għadhom qed
xi aħmar fil hemmhekk.

688
00:34:33,300 --> 00:34:35,540
Jekk inti stajt qatt semgħu l-akronimu RGB -

689
00:34:35,540 --> 00:34:36,830
aħmar, aħdar, blu -

690
00:34:36,830 --> 00:34:39,110
huwa li jirreferu għal din il-kompożizzjoni
ta 'immaġini li jużaw

691
00:34:39,110 --> 00:34:40,230
biss dawk it-tliet kuluri.

692
00:34:40,230 --> 00:34:43,159
U d-dritt issa, konna tintrema
kollha aħdar, kollha blu, imma

693
00:34:43,159 --> 00:34:44,500
hemm Ma tantx aħmar.

694
00:34:44,500 --> 00:34:45,920
>> So let me crank up l-aħmar.

695
00:34:45,920 --> 00:34:47,070
Kif nista 'nagħmlu?

696
00:34:47,070 --> 00:34:49,300
Ukoll, l-ewwel, jien ser jistaqsu
dan il-programm kwistjoni.

697
00:34:49,300 --> 00:34:52,030
Jien ser jimxi 'l quddiem u ejja sejħa hija
varjabbli, bħal fl-alġebra.

698
00:34:52,030 --> 00:34:54,060
Inti jista 'jkollhom x jew y jew z.

699
00:34:54,060 --> 00:34:57,230
Jien ser tiddikjara varjabbli
u jgħidu, imqiegħda fil dan il-varjabbli,

700
00:34:57,230 --> 00:35:02,790
temporanjament, il-valur tal-
immaġini valur getRed fil x, y.

701
00:35:02,790 --> 00:35:05,870
>> U għal darb'oħra, aħna ser terga 'lura għal kulħadd
ta 'dan id-dettall fil-futur.

702
00:35:05,870 --> 00:35:10,630
Iżda għal issa, ħu fuq il-fidi li
din il-linja hija titlob lill-programm, liema

703
00:35:10,630 --> 00:35:12,740
huwa l-valur aħmar fuq x, y?

704
00:35:12,740 --> 00:35:14,450
F'dak dot partikolari?

705
00:35:14,450 --> 00:35:15,710
>> Imbagħad jien ser tagħmel xi ħaġa biex dan.

706
00:35:15,710 --> 00:35:21,100
Imbagħad jien ser tagħmel image dot sett aħmar
fil x, y, y iżda din id-darba jien ser

707
00:35:21,100 --> 00:35:24,760
jsaħħuha billi tagħmel drabi aħmar,
ejja ngħidu, 10.

708
00:35:24,760 --> 00:35:26,870
Allura żżidu b'fattur ta '10.

709
00:35:26,870 --> 00:35:29,880
Let me zoom out issa u
click tista Mexxi / Save.

710
00:35:29,880 --> 00:35:36,430
U voila, li kien hemm l-kollu
żmien, għalkemm għajnejn tal-bniedem tagħna

711
00:35:36,430 --> 00:35:37,900
ma setax pjuttost tara dan.

712
00:35:37,900 --> 00:35:41,470
>> Għalhekk għal darb'oħra, issa din hija kodiċi reali, l-
Eżempju ta 'lingwa li aħna ser jidħlu

713
00:35:41,470 --> 00:35:42,770
lura għall-qabel twil.

714
00:35:42,770 --> 00:35:46,670
Iżda realizzata, b'mod partikolari dawk tal inti
bl-ebda esperjenza bħal din, huwa pjuttost

715
00:35:46,670 --> 00:35:50,280
hekk li aħna lilna nfusna se jkun
kodiċi miktub bħal dik hemmhekk.

716
00:35:50,280 --> 00:35:54,520
Fil-fatt, għodda li magħhom inti qed kollha
kemmxejn familjari, forsi, huwa l-CS50

717
00:35:54,520 --> 00:35:57,330
stess kors-shopping għodda, li kienet
attwalment fasslu dan is-sajf minn xi

718
00:35:57,330 --> 00:36:01,070
ex-studenti CS50 stess,
issa għandha ddur TFS.

719
00:36:01,070 --> 00:36:04,740
>> Allura dan jiġri li jkun website mibnija
f'lingwa imsejjaħ PHP.

720
00:36:04,740 --> 00:36:08,510
Hija tuża database imsejjaħ MySQL, l-affarijiet
li aħna ser jiksbu l-idejn tagħna

721
00:36:08,510 --> 00:36:10,190
maħmuġin aktar tard fil-semestru.

722
00:36:10,190 --> 00:36:14,140
Imma temmen jew le, anke xi ħaġa
bħal dan finalment inaqqas il-

723
00:36:14,140 --> 00:36:19,480
sempliċi ta 'loops u kondizzjonijiet u
fergħat, bħal dawk rajna biss

724
00:36:19,480 --> 00:36:21,530
mument ilu fil-video TED.

725
00:36:21,530 --> 00:36:25,180
>> What I ħsibt I d tagħmel issa huwa s-sehem ma jkunx
biss xi ħaġa li aħna l-istaff għamlu

726
00:36:25,180 --> 00:36:28,010
għall-kampus, iżda pjuttost xi ħaġa
ex student - tlieta

727
00:36:28,010 --> 00:36:29,080
istudenti, fil-fatt -

728
00:36:29,080 --> 00:36:33,950
magħmula din is-sena li għaddiet, Sierra, Daniel, u
Sam, l-aħħar minnhom kellhom ebda minn qabel

729
00:36:33,950 --> 00:36:36,370
esperjenza programing
meta ħa CS50.

730
00:36:36,370 --> 00:36:39,950
U għall-proġett finali tagħhom, huma
esibit, fil-Fiera CS50, l-

731
00:36:39,950 --> 00:36:43,720
applikazzjoni msejħa wrdly, li hija
programm fuq l-internet li għalihom huma jkunu għamlu

732
00:36:43,720 --> 00:36:47,670
dan il-video li ħsibt I d jaqsmu
jagħtuk sens ta 'x'inhu

733
00:36:47,670 --> 00:36:49,280
possibbli sa tmiem tul ta '.

734
00:36:49,280 --> 00:37:57,170
>> [Daqq tal-mużika]

735
00:37:57,170 --> 00:38:00,570
>> DAVID Malan: C'est minn Zero Ġimgħa
sa Ġimgħa 12 din is-sena li għaddiet.

736
00:38:00,570 --> 00:38:05,470
>> [Applause]

737
00:38:05,470 --> 00:38:09,520
>> DAVID Malan: Bħala teaser, wisq, tassew
biex iqabbduk aptit tiegħek huwa li x'hemm

738
00:38:09,520 --> 00:38:14,580
possibbli, inti tista raw diġà,
jew jista 'malajr tara, market.cs50.net, a

739
00:38:14,580 --> 00:38:17,710
għodda ġdida li t-tim tal-kors ma għandha
ilhom jaħdmu fuq, din id-darba

740
00:38:17,710 --> 00:38:21,530
kollaborazzjoni ma Student Harvard
Aġenziji, tali li jibdew din is-sena

741
00:38:21,530 --> 00:38:24,980
u kontinwu nisperaw fis dan
ġejjin sajf inti ser ikollok standard

742
00:38:24,980 --> 00:38:27,890
opportunità fuq il-kampus li jixtru u
jbiegħu affarijiet ta 'interess għalik.

743
00:38:27,890 --> 00:38:32,220
U ma 'sħubija permezz HSA, inti ser
ukoll ikunu kapaċi li qatra oġġetti off

744
00:38:32,220 --> 00:38:35,950
f'wieħed mill-ħwienet fiżiċi HSA tal f'xi
punt fil-ġejjieni, sabiex

745
00:38:35,950 --> 00:38:39,150
affarijiet prokura, partikolarment kif inti
gradwati u ma neċessarjament jixtiequ li

746
00:38:39,150 --> 00:38:44,110
jarmi affarijiet, imma attwalment tħallas
tibgħat lill folks li jistgħu warajk

747
00:38:44,110 --> 00:38:45,270
hawn fuq il-kampus.

748
00:38:45,270 --> 00:38:46,740
Allura aktar fuq li li ġejjin.

749
00:38:46,740 --> 00:38:49,830
>> Iżda ftit aktar konkret, għodda
thats toħroġ CS50 fl-aħħar

750
00:38:49,830 --> 00:38:52,760
snin, li magħhom xi wħud minnkom jista 'jkun
familjari u oħrajn minnkom jista 'jkun

751
00:38:52,760 --> 00:38:57,940
googling issa, fil CS50.net/2x, inti ser
issib link għal estensjoni Chrome

752
00:38:57,940 --> 00:39:01,250
li hija dimostrattiv ta 'kif inti tista'
użu JavaScript, f'dik il-lingwa aħna

753
00:39:01,250 --> 00:39:06,660
jintużaw mal-torri Eiffel mument ilu,
biex jimplimentaw veloċità daqq 2x

754
00:39:06,660 --> 00:39:09,000
għall-videos iSites Harvard.

755
00:39:09,000 --> 00:39:11,880
Din hija xi ħaġa li jinbnew
fis video player CS50 stess.

756
00:39:11,880 --> 00:39:14,870
Iżda dan, wisq, jekk inti tibda biex ħaffer
fil-kodiċi tas-sors, li aħna ser

757
00:39:14,870 --> 00:39:18,840
heureusement jagħmlu disponibbli, tkun taf tara kif
inti tista 'anki isolvu problemi bħal dik,

758
00:39:18,840 --> 00:39:23,180
aċċellerazzjoni widgets fil-websajts ma
li int diġà familjari sew.

759
00:39:23,180 --> 00:39:26,630
>> Allura kelma issa dwar il-kors u
aspettattivi u dak li jinsab quddiem.

760
00:39:26,630 --> 00:39:29,445
B'mod ġenerali, aħna ser tabilħaqq jiġbru hawn
nhar ta 'Tnejn u l-Erbgħa - għalkemm

761
00:39:29,445 --> 00:39:31,490
din il-ġimgħa, aħna ser tiġbor minħabba
ta 'Xiri Ġimgħa -

762
00:39:31,490 --> 00:39:34,640
1:00-14:00, għalkemm
kultant sa 02:30.

763
00:39:34,640 --> 00:39:38,700
Minħabba li inti tista 'tixtieq għaldaqstant jew
għandek tieħu xi klassi fil 02:00

764
00:39:38,700 --> 00:39:42,480
onward, jew saħansitra qabel, do jirrealizzaw il-
kors huwa ta 'appoġġ ta' dak li sejjaħ

765
00:39:42,480 --> 00:39:45,900
reġistrazzjoni simultanja, fejn aħna ser
appoġġ petizzjoni lill-Bord Ad u

766
00:39:45,900 --> 00:39:49,400
residenti Deans tiegħek f'ismek jekk
għandek kunflitt x'imkien f'din

767
00:39:49,400 --> 00:39:50,790
1:00-02:30 firxa.

768
00:39:50,790 --> 00:39:54,110
Head sa dak URL online għal
dettalji addizzjonali.

769
00:39:54,110 --> 00:39:57,750
>> Imma f'termini ta 'l-istruttura ta' appoġġ
li jikkaratterizza CS50, għall-istudenti

770
00:39:57,750 --> 00:40:01,750
aktar u anqas komdi bl-istess mod, aħna
joffru binarji distinti ta 'taqsimiet.

771
00:40:01,750 --> 00:40:04,730
U dan huwa ftit ġimgħat off, iżda
qabel twil, inti ser tintalab biex

772
00:40:04,730 --> 00:40:05,770
livell ta 'kumdità tiegħek.

773
00:40:05,770 --> 00:40:08,590
Inti fost dawk inqas komdi,
aktar komda, jew

774
00:40:08,590 --> 00:40:10,520
x'imkien bejniethom?

775
00:40:10,520 --> 00:40:13,150
>> U aħna ser ikollhom tliet distinti
binarji li jaħsbu għal

776
00:40:13,150 --> 00:40:14,470
preċiżament dawk udjenzi.

777
00:40:14,470 --> 00:40:17,900
Allura fl-ebda punt fit-terminu għandek
anki jħossu bħal int jikkompetu

778
00:40:17,900 --> 00:40:21,390
kontra kull student b'aktar
jew l-isfond inqas milli suppost.

779
00:40:21,390 --> 00:40:24,160
Tabilħaqq, il-kors huwa maħsub li jkun
ħafna aktar kollaborattiv u ħafna

780
00:40:24,160 --> 00:40:25,650
aktar miftuħa minn dak.

781
00:40:25,650 --> 00:40:29,030
>> F'termini tas-settijiet problema, inti ser
ssib, ukoll, li minbarra l-

782
00:40:29,030 --> 00:40:32,130
edizzjoni standard ta 'problema kull ġimgħa
stabbiliti, hemm ħafna drabi "Hacker

783
00:40:32,130 --> 00:40:37,010
Edizzjoni "li kien ifisser li jiġu mmirati
fil-5% sa 10% jew b'tali mod tal-

784
00:40:37,010 --> 00:40:40,270
demografika li l tabilħaqq fost dawk
aktar komdu u tixtieq iktar

785
00:40:40,270 --> 00:40:43,960
ta 'sfida mill-istandard
edizzjoni ta 'dak pset jistenna.

786
00:40:43,960 --> 00:40:46,390
Aktar dettalji dwar dawk li jkunu
misjuba fis-sillabu.

787
00:40:46,390 --> 00:40:49,430
>> Iżda wkoll fil hemm jistgħu jinstabu d-dettalji
dwar il-korsijiet jiem tard.

788
00:40:49,430 --> 00:40:51,570
Tipikament problema settijiet
huma dovuti nhar ta 'Ħamis.

789
00:40:51,570 --> 00:40:55,550
Madankollu, inti tista 'testendi ħafna tiegħek
iskadenzi dan it-tnaqqis mill-Hamis li

790
00:40:55,550 --> 00:41:00,010
Ġimgħa sempliċement billi jissodisfa magħna f'nofsu,
biex ngħidu hekk, li jwieġeb warm-up ftit

791
00:41:00,010 --> 00:41:03,370
mistoqsijiet f'xi wħud mill-problema tal-ġimgħa
settijiet, li se awtomatikament

792
00:41:03,370 --> 00:41:05,710
imbagħad jagħtik extra 24 siegħa.

793
00:41:05,710 --> 00:41:09,120
Aħna se qatra wkoll aktar baxx tiegħek
punteġġ, kif fis-sillabu.

794
00:41:09,120 --> 00:41:12,170
>> Biex jagħtuk sens ta 'dak l-problema
settijiet huma - għaliex dan huwa tabilħaqq

795
00:41:12,170 --> 00:41:15,120
problema tal-kors ta 'settijiet li
finalment jiddefinixxu kważi kull

796
00:41:15,120 --> 00:41:18,760
esperjenza istudent, aktar minn hekk
lectures, aktar minn sezzjonijiet, aktar

797
00:41:18,760 --> 00:41:21,230
minn hekk aktar xi oħra
aspett tal-kors.

798
00:41:21,230 --> 00:41:25,140
Sena li għaddiet, per eżempju, bdejna, kif
aħna ser jibdew din is-sena, bl Scratch.

799
00:41:25,140 --> 00:41:29,150
Partikolarment dan il-ġimgħa, aħna ser juża, per
jum wieħed biss darba, a grafika

800
00:41:29,150 --> 00:41:32,260
lingwa ta 'programmar, li aħna ser
tibda programmazzjoni billi jittrattienu u

801
00:41:32,260 --> 00:41:37,580
twaqqa biċċiet puzzle li huma biss
jimmuntaw fiżikament jekk jagħmel sens

802
00:41:37,580 --> 00:41:38,990
biex jagħmlu dan loġikament.

803
00:41:38,990 --> 00:41:43,460
>> Ġimgħa d-dieħla, aħna ser malajr tranżizzjoni għal
C, pjuttost antiki iżda żgħar ħafna u

804
00:41:43,460 --> 00:41:48,510
lingwa sempliċi li se jippermettilna naslu biex
verament jmorru 0-60 matul il-kors

805
00:41:48,510 --> 00:41:52,290
ta 'ftit ftit ġimgħat, u mbagħad parlay
dawk l-istess ħiliet u għarfien ta '

806
00:41:52,290 --> 00:41:56,160
constructs programmazzjoni bażiċi fis
lingwi ta 'livell ogħla bħall-PHP,

807
00:41:56,160 --> 00:41:58,240
JavaScript, u ​​oħrajn għadhom xorta.

808
00:41:58,240 --> 00:42:02,560
>> Sena li għaddiet, it-tielet pset fil-kors
kienet dik ta kriptografija, a

809
00:42:02,560 --> 00:42:06,380
applikazzjoni speċifika dominju li biha aħna
istudenti ikkontestata biex timplimenta kull

810
00:42:06,380 --> 00:42:11,140
numru ta 'ciphers, programmi li
ġirja jew unscramble informazzjoni,

811
00:42:11,140 --> 00:42:11,880
biex kriptaġġ.

812
00:42:11,880 --> 00:42:16,300
Għall-edizzjoni Hacker, b'kuntrast,
aħna taw l-istudenti Hacker fajl

813
00:42:16,300 --> 00:42:19,900
minn kompjuter standard Unix fihom
ismijiet utent u passwords,

814
00:42:19,900 --> 00:42:22,740
l-aħħar minnhom kienu encrypted,
u aħna kkontestat dawk Hacker

815
00:42:22,740 --> 00:42:26,850
studenti li decrypt, mill-aħjar li jistgħu,
dawk passwords, dejjem fuq dan

816
00:42:26,850 --> 00:42:27,770
istess dominju.

817
00:42:27,770 --> 00:42:30,580
>> Ġirja, logħba li xi
minnkom huma familjari forsi.

818
00:42:30,580 --> 00:42:34,410
Biċċa forensika, fejn aħna nitolbu istudenti
biex jirkupraw data li kienu

819
00:42:34,410 --> 00:42:38,530
inkella mħassra mill diġitali tiegħi stess
flash card kompatti kamera, billi

820
00:42:38,530 --> 00:42:42,740
fatt bil-miktub software biex insemmu,
fejn kienu l zeroes u dawk fil-

821
00:42:42,740 --> 00:42:46,850
li kamera diġitali li qabel
komposta grafika JPEG?

822
00:42:46,850 --> 00:42:49,710
>> Sfida ta 'tipi aħħar sena
li jinvolvi kitba l-iktar mgħaġġla

823
00:42:49,710 --> 00:42:53,160
jespliċitaw-kontrollur jista 'jkun, jikkompetu
kontra l-ħbieb u l-klassi jekk

824
00:42:53,160 --> 00:42:53,860
li tixtieq.

825
00:42:53,860 --> 00:42:56,330
Implimentazzjoni n Puff Huff ",
programm kompressjoni.

826
00:42:56,330 --> 00:43:01,930
U mbagħad jispiċċa l-semestru mal-CS50
Finanzi, applikazzjoni web-based ma

827
00:43:01,930 --> 00:43:06,570
li inti toħloq websajt Etrade-like
li jixtru u jbigħu l-ħażniet, biex

828
00:43:06,570 --> 00:43:09,860
jitkellmu, billi attwalment ġbid kważi
fil-ħin reali kwotazzjonijiet Yahoo!

829
00:43:09,860 --> 00:43:10,450
Finanzi.

830
00:43:10,450 --> 00:43:13,590
>> Dak li aħna ma tagħmel aħħar sena kien
problema sett wieħed li jibqa '

831
00:43:13,590 --> 00:43:14,810
madankollu favoriti.

832
00:43:14,810 --> 00:43:18,400
Jekk inti stajt qatt marret biex
shuttle.cs50.net, tkun taf tara utent

833
00:43:18,400 --> 00:43:19,670
interface ftit bħal dan.

834
00:43:19,670 --> 00:43:23,530
Iżda sentejn ilu, il-klassi
implimentati, bl-użu Google Maps u l-

835
00:43:23,530 --> 00:43:28,570
Google Earth plug-in u xi ftit
ta 'sofistikati mal sewqan madwar il-kampus,

836
00:43:28,570 --> 00:43:33,290
b'tali mod li l-objettiv ta 'din il-logħba kienet,
kif tista 'tara xi wħud mill-uċuħ,

837
00:43:33,290 --> 00:43:37,530
huwa li jsuq madwar kampus tfittex
persunal, fellows tagħlim u CAS, u

838
00:43:37,530 --> 00:43:40,080
meta inti tagħmel, jqiegħduhom
fuq bus shuttle tiegħek.

839
00:43:40,080 --> 00:43:44,035
Ħadd minnhom attwalment jidhru li jkun hawn,
hekk aħna qed tmur biex jidħol iqarrqu kodiċi.

840
00:43:44,035 --> 00:43:47,150
>> [Daħk]

841
00:43:47,150 --> 00:43:48,430
>> DAVID Malan: Hemm immorru.

842
00:43:48,430 --> 00:43:49,240
Kull dritt.

843
00:43:49,240 --> 00:43:51,750
U hawn issa huwa l-persunal
mwaħħlin matul kampus.

844
00:43:51,750 --> 00:43:54,530
U kif tista 'tara, fuq il-lemin
ġenb tal-iskrin, il-bus shuttle

845
00:43:54,530 --> 00:43:55,510
jkollha sedili vojta.

846
00:43:55,510 --> 00:43:59,000
U l-għan kien li tikteb il-
kodiċi li biex jissimulaw dan

847
00:43:59,000 --> 00:44:01,790
sewqan u picking up u twaqqa
off tal-passiġġieri.

848
00:44:01,790 --> 00:44:04,960
Li wieħed, wisq, bl-użu ta 'lingwa
imsejħa JavaScript.

849
00:44:04,960 --> 00:44:10,030
Allura jirrealizzaw li l-programmi bħal li se
tkun fuq istess trajettorja tagħna din

850
00:44:10,030 --> 00:44:10,910
sena, kif ukoll.

851
00:44:10,910 --> 00:44:13,640
>> F'termini, issa, ta 'appoġġ addizzjonali,
għandna ħinijiet tal-uffiċċju.

852
00:44:13,640 --> 00:44:16,520
Kif inti tista raw fid-dar tiegħek stess
dining sala jew Annenberg,

853
00:44:16,520 --> 00:44:19,280
aħna ser tkun fil-dining dar
swali erba iljieli fil-ġimgħa -

854
00:44:19,280 --> 00:44:24,450
Leverett, Pfoho, Eliot u Annenberg
din is-sena, 20:00-23:00.

855
00:44:24,450 --> 00:44:26,830
U dak ħsibna aħna'd jagħmlu din is-sena
hija xi ftit differenti.

856
00:44:26,830 --> 00:44:29,650
>> Jekk smajtu rumblings aħħar sena li
kien daqsxejn wisq stressanti, dan

857
00:44:29,650 --> 00:44:32,800
ħinijiet tal-uffiċċju sena, kif aħna ser jiddeskrivu
ġimgħa d-dieħla, se tkun aktar organiku,

858
00:44:32,800 --> 00:44:36,900
fejn mal-wasla, inti ser tkun
mibgħuta lil wieħed tabella partikulari

859
00:44:36,900 --> 00:44:39,860
fejn il-membri tal-persunal multipli tistenna,
u aħna ser nagħmlu l-affarijiet ħafna aktar

860
00:44:39,860 --> 00:44:40,440
organikament.

861
00:44:40,440 --> 00:44:43,740
Nru aktar kju, mhux aktar iPad, iżda
pjuttost jkollhom aktar intimi

862
00:44:43,740 --> 00:44:47,300
konversazzjonijiet madwar mejda ta 'ftit
tmien jew hekk istudenti, sabiex inkunu

863
00:44:47,300 --> 00:44:50,880
approssimattiv l-jħossu ta 'dak li altrimenti
ikun klassi ferm iżgħar.

864
00:44:50,880 --> 00:44:54,120
>> Noffru, kif ukoll, dawn l-affarijiet aħna
imsejħa walkthroughs, videos iffilmjati

865
00:44:54,120 --> 00:44:57,330
qabel minn waħda mill-kors ta 'tagħlim tal-
fellows, Zamyla, fejn hi

866
00:44:57,330 --> 00:45:00,690
mixjiet inti permezz problema tal-ġimgħa
settijiet, li joffru tips u tricks għall-

867
00:45:00,690 --> 00:45:02,640
isfidi li jistabbilixxu l quddiem.

868
00:45:02,640 --> 00:45:06,230
U bil-maqlub, wara settijiet problema huma
dovut, din is-sena, aħna ser rilaxx wkoll

869
00:45:06,230 --> 00:45:09,100
clips ftit sejħa awtopsji li
attwalment jimxu miegħek permezz

870
00:45:09,100 --> 00:45:13,630
soluzzjonijiet rappreżentattivi, tnejn tajbin u
bad, permezz li inti tista 'tiddeduċi kif

871
00:45:13,630 --> 00:45:17,550
inti jista 'jkollhom jew għandu jkollhom
implimentat soluzzjoni tiegħek stess.

872
00:45:17,550 --> 00:45:20,500
>> U dak li aħna ser joffru għall-ewwel darba
din is-sena kif ukoll, partikolarment

873
00:45:20,500 --> 00:45:23,420
għal dawk l-istudenti li jagħmlu użu
tal-kors tal-oħra

874
00:45:23,420 --> 00:45:28,580
riżorsi iżda madankollu qed jitħabtu
kollha wisq, il-kors

875
00:45:28,580 --> 00:45:33,030
innifsu se par dawk l-istudenti, kif
riżorsi jippermettu, b'għalliema sabiex

876
00:45:33,030 --> 00:45:35,840
għandek ħafna aktar intimi
opportunità minn swali dining dar

877
00:45:35,840 --> 00:45:38,700
jippermettu għall-għajnuna one-on-one.

878
00:45:38,700 --> 00:45:42,780
>> Issa idea finali f'xi
tal-logħob għan fil-vista.

879
00:45:42,780 --> 00:45:44,580
Inti jista 'jkun familjari ma'
l-Hackathon CS50.

880
00:45:44,580 --> 00:45:48,120
Well, li ġejjin din Diċembru, minn 08:00
PM biex 7:00, fil-bidu ta '

881
00:45:48,120 --> 00:45:51,410
Qari Perjodu, ser tkun opportunità
biex tiġbor mal-klassi -

882
00:45:51,410 --> 00:45:53,130
din tkun ta 'madwar 9:00 -

883
00:45:53,130 --> 00:45:56,550
waqt li inti adsa fis finali tiegħek
implimentazzjoni proġett flimkien

884
00:45:56,550 --> 00:45:59,910
klassi, ħbieb, u l-ikel.

885
00:45:59,910 --> 00:46:03,680
Dan ikun madwar 01:00, meta
l-ewwel lott ta 'ikel waslu.

886
00:46:03,680 --> 00:46:08,470
U dan huwa dwar 04:00 li
sena partikolari fil-Hackathon CS50.

887
00:46:08,470 --> 00:46:12,000
>> Iżda l-qofol veru tal-kors huwa
maħsuba għall-Fiera CS50, il-kampus kollha

888
00:46:12,000 --> 00:46:15,790
wirja ta 'proġetti finali tiegħek,
li familja u ħbieb huma kollha

889
00:46:15,790 --> 00:46:18,730
mistiedna, kif jirrekluta tagħna u
ħbieb tagħna mill-industrija.

890
00:46:18,730 --> 00:46:22,170
Dan, per eżempju, huwa idea ta 'l-
Nies 2,000 plus li stajt attendew

891
00:46:22,170 --> 00:46:23,160
aħħar snin.

892
00:46:23,160 --> 00:46:27,180
Espressjonijiet bħal din mhumiex komuni,
u l-istess tagħmel tiegħek

893
00:46:27,180 --> 00:46:29,660
klassi delight fl-affarijiet
inti stajt jitlestew.

894
00:46:29,660 --> 00:46:33,170
>> U fil-fatt, lejn dak il-għan, għandna
avveniment start-of-tul, kif ukoll.

895
00:46:33,170 --> 00:46:37,400
Jekk l-affarijiet bħal dan l-appell lilek, jew
int inqas kurjużi dwar liema

896
00:46:37,400 --> 00:46:41,590
dan, jafu li tradizzjoni ġdida tal-
kors huwa msejjaħ CS50 Jum Puzzle.

897
00:46:41,590 --> 00:46:45,710
U dan kien istitwit koppja ta '
snin lura biex verament jagħtu x'jifhem lill kampus

898
00:46:45,710 --> 00:46:48,930
li x-xjenza tal-kompjuter mhix dwar
programmazzjoni, u huwa ċertament mhux

899
00:46:48,930 --> 00:46:51,960
madwar tħaddan biss dawk l-istudenti
li jkollhom esperjenza minn qabel.

900
00:46:51,960 --> 00:46:54,200
Huwa verament dwar soluzzjoni ta 'problemi
b'mod aktar ġenerali.

901
00:46:54,200 --> 00:46:57,360
>> U hekk Puzzle Day, matul l-aħħar ftit
snin issa, evolviet sbieħ

902
00:46:57,360 --> 00:47:00,500
sħubija mal-ħbieb tagħna fuq
Facebook, fejn se jkun hemm fabulous

903
00:47:00,500 --> 00:47:04,830
premjijiet u pizza madwar l-xmara fil
l-i-lab din is-Sibt li ġej.

904
00:47:04,830 --> 00:47:09,180
Ras għal dak URL b'żewġ jew tliet
ħbieb jekk inti tixtieq li jieħdu sehem

905
00:47:09,180 --> 00:47:10,830
f'dan tradizzjoni ġdida.

906
00:47:10,830 --> 00:47:14,180
>> So I tixtieq li jistaqsu li inti żżomm wieħed
ħaġa fil-moħħ, u konna ltqajna biss

907
00:47:14,180 --> 00:47:17,070
żewġ minuti clip li fuqhom
li tagħlaq illum.

908
00:47:17,070 --> 00:47:19,640
73% huwa n-numru li wieħed jiftakru.

909
00:47:19,640 --> 00:47:23,900
Kejk, ukoll, se tistenna int barra dan
kappelluni kif aħna jiddifferixxi fi ftit

910
00:47:23,900 --> 00:47:26,710
Koppja ta 'mumenti, li huwa tradizzjoni
tal-kors, kif ukoll.

911
00:47:26,710 --> 00:47:29,860
Iżda dan huwa l-kwotazzjoni ewlenija mill-
sillabus tal-kors li wieħed iżomm f'moħħu.

912
00:47:29,860 --> 00:47:32,820
Dak finalment importanti f'dan il-kors
huwa mhux tant fejn inti tispiċċa

913
00:47:32,820 --> 00:47:36,580
relattiva għal klassi tiegħek imma fejn
inti, fil-Ġimgħa 12, jispiċċaw relattiva għal

914
00:47:36,580 --> 00:47:37,960
ruħek fil f'Ġimgħa 0.

915
00:47:37,960 --> 00:47:43,670
>> Iżda l-idea li aħna ser tħallik
ma hawn illum huwa dan l-aħħar wieħed hawn

916
00:47:43,670 --> 00:47:47,580
minn Daniel istess tagħna, li ma l-
video wrdly ftit mument ilu.

917
00:47:47,580 --> 00:47:50,000
I leave inti ma 'dan glimpse
ta 'dak li jinsab quddiem.

918
00:47:50,000 --> 00:47:53,360
U kif nagħmlu dan, jekk jista 'jkollna CS50
persunal mill-quddiem tal-kamra

919
00:47:53,360 --> 00:47:57,280
li ġejjin fuq sa l-istadju li żebgħa kollha
l-aktar ta 'stampa viżwali biex

920
00:47:57,280 --> 00:47:59,100
dak li jistenna inti din is-sena -

921
00:47:59,100 --> 00:48:00,350
jkollna skomdi.

922
00:48:00,350 --> 00:48:02,200

923
00:48:02,200 --> 00:48:05,188
Aħna ser tikkonkludi ma 'dan
hawn fuq l-iskrin.

924
00:48:05,188 --> 00:48:18,634
>> [Daqq tal-mużika]

925
00:48:18,634 --> 00:48:21,124
>> DAVID Malan: Dan huwa CS50.

926
00:48:21,124 --> 00:50:00,226
>> [MUSIC - MATT & KIM, "IT alright"]

927
00:50:00,226 --> 00:50:03,245
>> SPEAKER 1: I love CS50 aktar minn qtates.

928
00:50:03,245 --> 00:50:06,030
>> SPEAKER 2: Whoaaaa!

929
00:50:06,030 --> 00:50:06,990
>> [Daħk]

930
00:50:06,990 --> 00:50:08,140
>> DAVID Malan: Dan, imbagħad, huwa CS50.

931
00:50:08,140 --> 00:50:10,050
Aħna se tara int nhar il-Ġimgħa.

932
00:50:10,050 --> 00:50:13,370
>> [Applause U cheering]

933
00:50:13,370 --> 00:50:17,540
>> Narrator: Fil-CS50 li jmiss, l onstage
demo ma tmurx kif ippjanat.

934
00:50:17,540 --> 00:50:19,080
>> DAVID Malan: Aħna rridu li jsibu Mike
Smith f'dan il-ktieb tat-telefon.

935
00:50:19,080 --> 00:50:20,380
Well, liema huma instincts tiegħek?

936
00:50:20,380 --> 00:50:23,750
I tista 'tiżdied bejn wieħed u ieħor man-nofs ta'
il-ktieb tat-telefon, t'għajn isfel, tara li

937
00:50:23,750 --> 00:50:26,830
Jien fil-M, u naf issa li Mike
Smith ma tkunx lejn ix-xellug.

938
00:50:26,830 --> 00:50:27,840
Huwa għandu jkun il-lemin.

939
00:50:27,840 --> 00:50:30,515
U hekk f'dan il-punt, aħna
jistgħu litteralment tiċrita -

940
00:50:30,515 --> 00:50:33,300
f'dan il-punt, nistgħu litteralment tiċrita -

941
00:50:33,300 --> 00:50:36,490
f'dan il-punt, nistgħu figurattivament
tiċrita l-ktieb tat-telefon fil nofs.

942
00:50:36,490 --> 00:50:38,954
>> [Strumming UKELELE]