1
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2
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[Daqq ta mużika]

3
00:00:03,340 --> 00:00:11,020

4
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>> DAVID Malan: Dan huwa CS50.

5
00:00:14,010 --> 00:00:18,090
U dan huwa kemm l-bidu u l-
end-- bħall literally-- kważi l-aħħar

6
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ta 'sitt ġimgħat.

7
00:00:18,825 --> 00:00:20,030

8
00:00:20,030 --> 00:00:22,640
>> Ħsibt I d jaqsmu
ftit ta 'fatt gost.

9
00:00:22,640 --> 00:00:25,370
Stajt jinġibed dan up minn
data semestru passat issettjat.

10
00:00:25,370 --> 00:00:29,710
Inti tista 'tfakkar li aħna nitolbuk fuq kull
p forma sett jekk inti stajt jarah online

11
00:00:29,710 --> 00:00:31,580
jew jekk inti stajt attendew personalment.

12
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U hawn huwa l-data.

13
00:00:33,020 --> 00:00:34,710
Hekk illum kien ferm prevedibbli.

14
00:00:34,710 --> 00:00:37,126
Imma ridna li jonfqu ftit
ta 'ħin miegħek xorta.

15
00:00:37,126 --> 00:00:40,599
Kieku xi ħadd tixtieq konġettura għaliex dan
graff hija tant jaggy, up isfel, up isfel,

16
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hekk konsistentement?

17
00:00:41,265 --> 00:00:42,980

18
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What do kull wieħed mill-qċaċet
u ħwat jirrappreżentaw?

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>> UDJENZA: [inaudible]

20
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DAVID Malan: Tabilħaqq.

22
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23
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U aktar divertenti, Alla jipprojbixxu,
aħna istiva taħdita waħda nhar ta 'Ġimgħa

24
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fil-bidu tas-semestru,
dan huwa dak li naraw jiġri.

25
00:00:58,960 --> 00:01:03,430
Hekk illum, aħna ikollhom sehem fl daqsxejn
aktar dwar strutturi ta 'dejta.

26
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U biex jagħtuk aktar ta 'solidu
mudell mentali għall-problemi fil-ħames,

27
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li huwa issa out.

28
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Misspellings, fejn, aħna ser
banda inti fajl test xi 100,000

29
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plus kliem Ingliż, u
int ser ikollhom

30
00:01:12,650 --> 00:01:17,770
biex insemmu kif cleverly jitgħabbew
fil-memorja, fis RAM, bl-użu xi data

31
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istruttura ta 'l-għażla tiegħek.

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>> Issa wieħed istruttura tad-data bħal seta
jkun, iżda probabbilment ma għandhiex tiġi,

33
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il-lista hija pjuttost simplistika marbuta,
li aħna introdotti aħħar darba.

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U lista marbuta kellhom mill-inqas
wieħed vantaġġ fuq firxa.

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X'hemm vantaġġ wieħed
lista marbuta forsi?

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>> UDJENZA: Inserzjoni.

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>> DAVID Malan: Inserzjoni.

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X'tifhem minn dik?

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>> UDJENZA: Kullimkien flimkien
il-lista [inaudible].

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>> DAVID Malan: Tajba.

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Allura inti tista 'daħħal element kulfejn
inti tixtieq fin-nofs tal-lista

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mingħajr ma jkollhom shuffle xejn,
li aħna kkonkludiet, fl issortjar tagħna

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diskussjonijiet, mhuwiex
bilfors ħaġa tajba,

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minħabba li jieħu ż-żmien biex attwalment jiċċaqalqu
kollha ta 'dawk bnedmin lemin jew xellug.

46
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U hekk ma 'lista marbuta, inti tista
biss jalloka malloc, node ġdid,

47
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u mbagħad taġġorna koppja ta '
pointers-- żewġ, tliet operazzjonijiet max--

48
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u aħna qed kapaċi li slots xi ħadd
fi kullimkien fi lista.

49
00:02:01,480 --> 00:02:03,550
>> X'iktar kien vantaġġuż
dwar lista marbuta?

50
00:02:03,550 --> 00:02:04,980

51
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Yeah?

52
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>> UDJENZA: [inaudible]

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00:02:06,534 --> 00:02:07,538

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DAVID Malan: Perfect.

55
00:02:08,413 --> 00:02:10,590

56
00:02:10,590 --> 00:02:11,090
Perfect.

57
00:02:11,090 --> 00:02:12,070
Huwa tassew dinamiku.

58
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U li int mhux jikkommettu,
bil-quddiem, sa ċertu daqs fiss

59
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blokki ta 'memorja, bħal inti jkollok
li ma 'firxa, il-rasu ta' liema

60
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hija li inti tista jalloka lymph biss fuq
domanda u b'hekk jintużaw biss bħala ħafna spazju

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kif inti attwalment ħtieġa.

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B'kuntrast ma 'firxa, inti tista
aċċidentalment jallokaw ftit wisq.

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U allura huwa biss se
li jkunu uġigħ fl-għonq

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li jirriallokaw firxa ġdida akbar, kopja
kollox fuq, tilliberalizza l-array qodma,

65
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u mbagħad jimxu dwar in-negozju tiegħek.

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00:02:33,990 --> 00:02:37,479
Jew agħar, inti tista 'talloka mod
memorja aktar milli suppost attwalment ħtieġa,

67
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u hekk int se jkollhom ħafna
firxa b'popolazzjoni skarsa, biex ngħidu hekk.

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>> Allura lista marbuta jagħtik dawn
vantaġġi ta 'dinamiżmu u l-flessibilità

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ma inserzjonijiet u tħassir.

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Iżda żgur għandu jkun hemm prezz imħallas.

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Fil-fatt, waħda mit-temi
esplorati fuq kwizz żero

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kien koppja ta 'l-kompromessi
Rajna s'issa.

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Allura x'hemm prezz imħallas jew ta '
negattivi ta 'lista marbuta?

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Yeah.

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>> UDJENZA: L-ebda aċċess bl-addoċċ.

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>> DAVID Malan: L-ebda aċċess bl-addoċċ.

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Iżda quién?

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Aċċess bl-addoċċ ma ħoss konvinċenti.

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>> UDJENZA: [inaudible]

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00:03:02,421 --> 00:03:04,865

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DAVID Malan: Eżattament.

82
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Jekk inti tixtieq li jkollok
a algorithm-- ċerta

83
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u let me attwalment tipproponi
tfittxija binarju, b'mod partikolari, li

84
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hija waħda konna użati pjuttost bit--
jekk inti ma għandekx aċċess bl-addoċċ,

85
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inti ma tistax tagħmel dan aritmetika sempliċi
ta 'konstatazzjoni bħall-element tan-nofs

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u jaqbeż dritt għaliha.

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Inti minflok għandek tibda fl-ewwel
element u lineari tfittxija mix-xellug

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biex id-dritt jekk inti tixtieq li ssib
nofs jew kwalunkwe element ieħor.

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>> UDJENZA: Huwa probabbilment jieħu memorja aktar.

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>> DAVID Malan: Jieħu memorja aktar.

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Fejn hi li addizzjonali
ispiża ġejjin minn fil-memorja?

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>> UDJENZA: [inaudible]

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DAVID Malan: Eżattament.

95
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F'dan il-każ hawnhekk, kellna
lista marbuta għall-interi,

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u għadhom aħna qed irduppjar
l-ammont tal-memorja

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għandna bżonn mill-ħażna wkoll dawn pointers.

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00:03:39,680 --> 00:03:42,090
Issa inqas ta 'big deal bħala
structs tiegħek tikseb akbar

99
00:03:42,090 --> 00:03:45,320
u int ħażna ma jkunx numru iżda
forsi student jew xi oġġett ieħor.

100
00:03:45,320 --> 00:03:46,880
Iżda l-punt ċertament tibqa.

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U għalhekk numru ta 'l-operazzjonijiet
fuq il-listi marbuta kienu jissejħu

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kienu O kbira ta 'lineari n--.

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Affarijiet simili inserzjoni jew tfittxija
jew tħassir fil-każ element

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li jkun ġara fl-aħħar nett ta '
il-lista jekk huwa magħżula jew le.

105
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>> Kultant inti tista 'tikseb xortik tajba u fil-
limiti hekk aktar baxxi fuq dawn l-operazzjonijiet

106
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Jista 'wkoll ikun ta' żmien kostanti jekk int
dejjem tħares lejn l-ewwel element,

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per eżempju.

108
00:04:05,070 --> 00:04:09,360
Iżda fl-aħħar, aħna imwiegħed
biex jintlaħaq l-Grail qaddis

109
00:04:09,360 --> 00:04:12,630
ta 'strutturi ta' dejta, jew
xi tieghu approssimazzjoni,

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00:04:12,630 --> 00:04:14,290
permezz ta 'ħin kostanti.

111
00:04:14,290 --> 00:04:17,579
Nistgħu nsibu l-elementi jew jiżdiedu elementi
jew tneħħi elementi minn lista?

112
00:04:17,579 --> 00:04:19,059
Ser naraw pjuttost malajr.

113
00:04:19,059 --> 00:04:21,100
U jirriżulta li wieħed
tal-mekkaniżmi aħna qed

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ser tibda tuża llum,
użu annwali fil-p sett ħamsa,

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huwa attwalment pretty familjari.

116
00:04:24,630 --> 00:04:27,430
Per eżempju, jekk dan huwa mazz
ta 'kotba eżami, li kull wieħed minnhom

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00:04:27,430 --> 00:04:29,660
għandha l-ewwel student
isem u l-aħħar isem fuqha,

118
00:04:29,660 --> 00:04:31,820
u I pick up lilhom minn
fl-aħħar ta 'eżami,

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u dawn qed kollha pretty
ħafna f 'ordni każwali,

120
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u rridu li tmur dwar għażla
dawn l-eżamijiet b'tali mod li ladarba gradati

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huwa biss ħafna aktar faċli u
aktar mgħaġġel biex jgħadduhom lura

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lill-istudenti alfabetikament.

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Liema jkun instincts tiegħek tkun
għal munzell ta 'eżamijiet bħal dan?

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>> Ukoll, jekk int simili me, inti
tista 'tara li dan huwa m,

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hekk jien ser tip ta 'tpoġġi dan fi,
jekk dan huwa mejda tiegħi jew mill-art tiegħi fejn

126
00:04:48,505 --> 00:04:50,650
Jien tixrid affarijiet
out-- jew firxa tiegħi really--

127
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I tista 'tpoġġi kollha ta' l Sinjura fil hemmhekk.

128
00:04:52,210 --> 00:04:52,710
Oh.

129
00:04:52,710 --> 00:04:55,020
Hawn A. So I jista
tpoġġi l-Kif hawn fuq.

130
00:04:55,020 --> 00:04:55,520
Oh.

131
00:04:55,520 --> 00:04:57,980
Hawn A. ieħor jien ser
biex iqiegħed dak hawn fuq.

132
00:04:57,980 --> 00:05:02,490
Hawn Z. Hawnhekk huwa M. ieħor U hekk
I tista 'tibda tagħmel munzelli bħal dan.

133
00:05:02,490 --> 00:05:06,620
U allura forsi I d jmorru fl aktar tard
u tip ta 'nitpicky-ly ħafna sort

134
00:05:06,620 --> 00:05:07,710
l-puntali individwali.

135
00:05:07,710 --> 00:05:11,300
Imma l-punt hu jien look
fid-dħul li jien f'idha

136
00:05:11,300 --> 00:05:14,016
u nixtieq tagħmel xi kkalkulat
deċiżjoni bbażata fuq dik input.

137
00:05:14,016 --> 00:05:15,640
Jekk jibda ma 'A, poġġih hemmhekk.

138
00:05:15,640 --> 00:05:18,980
Jekk jibda ma 'Z, poġġih fuq
hemm, u kollox bejniethom.

139
00:05:18,980 --> 00:05:22,730
>> Allura dan huwa teknika li l-
ġeneralment magħrufa bħala hashing-- H-A-S-H--

140
00:05:22,730 --> 00:05:26,550
li ġeneralment ifisser li jieħdu bħala
input u l-użu li l-kontribut biex tiġi kkalkulata

141
00:05:26,550 --> 00:05:30,940
valur, ġeneralment numru, u li
in-numru huwa l-indiċi fil-ħażna

142
00:05:30,940 --> 00:05:32,260
kontenitur, bħal firxa.

143
00:05:32,260 --> 00:05:35,490
Allura fi kliem ieħor, I jista 'jkollhom
funzjoni hash, kif nagħmel in my head,

144
00:05:35,490 --> 00:05:37,940
li jekk nara xi ħadd huwa
isem li tibda bil A,

145
00:05:37,940 --> 00:05:40,190
Jien ser mappa li
għal żero fl my head.

146
00:05:40,190 --> 00:05:44,160
U jekk nara xi ħadd bil Z, jien
ser Mappa li biex 25 in my head

147
00:05:44,160 --> 00:05:46,220
u mbagħad titqiegħed dan in
l-aħħar pile aktar.

148
00:05:46,220 --> 00:05:50,990
>> Issa, jekk inti taħseb dwar li ma moħħ tiegħi
iżda programm C, liema numri jista

149
00:05:50,990 --> 00:05:53,170
inti tistrieħ fuq biex jintlaħaq dak l-istess riżultat?

150
00:05:53,170 --> 00:05:55,594
Fi kliem ieħor, jekk inti
kellu l-ASCII karattru A,

151
00:05:55,594 --> 00:05:57,510
kif taħseb li jiddeterminaw
dak barmil li tqiegħed fil?

152
00:05:57,510 --> 00:05:59,801
You probabbilment ma jridux
poġġih fil-barmil 65, li

153
00:05:59,801 --> 00:06:01,840
ikun simili hemmhekk
għall-ebda raġuni tajba.

154
00:06:01,840 --> 00:06:04,320
Fejn do inti tixtieq li tqiegħed A
f'termini ta 'valur ASCII tagħha?

155
00:06:04,320 --> 00:06:05,600

156
00:06:05,600 --> 00:06:08,920
Fejn do inti tixtieq li tagħmel biex ASCII tagħha
valur li toħroġ bi barmil aktar intelliġenti

157
00:06:08,920 --> 00:06:09,480
li tqiegħed fil?

158
00:06:09,480 --> 00:06:10,206
>> UDJENZA: Minus A.

159
00:06:10,206 --> 00:06:10,956
>> DAVID Malan: Yeah.

160
00:06:10,956 --> 00:06:13,190
Allura minus A jew minus
speċifikament 65 jekk huwa

161
00:06:13,190 --> 00:06:18,240
kapital A. Jew 98 jekk
huwa zghar a.

162
00:06:18,240 --> 00:06:21,300
U hekk li tippermetti magħna biex, ħafna
sempliċi u aritmetikament ħafna,

163
00:06:21,300 --> 00:06:23,260
xi ħaġa fi barmil bħal dik.

164
00:06:23,260 --> 00:06:26,010
Għalhekk jirriżulta li għandna attwalment nagħmlu
dan ukoll anke mal-kwiżż.

165
00:06:26,010 --> 00:06:29,051
>> Allura inti tista 'recall inti circled tiegħek
isem sħabi tagħlim fuq il-qoxra.

166
00:06:29,051 --> 00:06:32,270
U ġew organizzati ismijiet tal-TF tal
f'dawn kolonni alfabetikament,

167
00:06:32,270 --> 00:06:34,400
ukoll, jemmnu jew le,
meta kollha 80 plus minna

168
00:06:34,400 --> 00:06:37,800
ltqajna flimkien oħra bil-lejl għall-grad,
l-aħħar pass fil-proċess ta 'gradazzjoni tagħna

169
00:06:37,800 --> 00:06:41,830
huwa li hash l kwizzijiet fi big
ispazju ta 'l-art fil-[inaudible]

170
00:06:41,830 --> 00:06:45,110
u li jiġu kwizzijiet kulħadd out
eżattament fl-ordni ta 'l TF tagħhom

171
00:06:45,110 --> 00:06:47,700
ismijiet fuq il-qoxra, għaliex
allura huwa ħafna aktar faċli għalina

172
00:06:47,700 --> 00:06:51,290
li tfittex li l-użu lineari
tfittxija jew xi tip ta 'cleverness

173
00:06:51,290 --> 00:06:54,050
għal TF biex isibu tiegħu jew
kwizzijiet istudenti tagħha ".

174
00:06:54,050 --> 00:06:56,060
>> Allura din l-idea ta 'hashing
li inti ser tara hija

175
00:06:56,060 --> 00:07:00,520
pjuttost qawwija huwa attwalment pretty
komuni ħafna u intuwittivi,

176
00:07:00,520 --> 00:07:03,000
ferm simili forsi jaqsam u
Conquer kien żero ġimgħa.

177
00:07:03,000 --> 00:07:05,250
I bil-ħerqa sew mal-hackathon
ftit ta 'snin ilu.

178
00:07:05,250 --> 00:07:08,040
Dan kien Zamyla u l-koppja ta '
studenti oħra greeting persunal

179
00:07:08,040 --> 00:07:09,030
kif daħal.

180
00:07:09,030 --> 00:07:12,680
U kellna mazz sħiħ ta 'tiwi
tabelli hemm ma tikketti l-isem.

181
00:07:12,680 --> 00:07:15,380
U kellna l-tikketti l-isem organizzata
mal bħall-AS fuq hemmhekk

182
00:07:15,380 --> 00:07:16,690
u l-Zs hemmhekk.

183
00:07:16,690 --> 00:07:20,350
U għalhekk wieħed mill-TFS ħafna cleverly
kiteb dan bħala l-istruzzjonijiet

184
00:07:20,350 --> 00:07:21,030
għall-jum.

185
00:07:21,030 --> 00:07:24,480
U fil-ġimgħa 12 tal-semestru dan
kollha magħmula sens perfetta u kulħadd

186
00:07:24,480 --> 00:07:25,310
kien jaf x'għandek tagħmel.

187
00:07:25,310 --> 00:07:27,900
Imma ghaċ inti stajt
kju bl-istess mod,

188
00:07:27,900 --> 00:07:30,272
int li timplimenta l-
istess kunċett ta 'hash.

189
00:07:30,272 --> 00:07:31,730
Mela ejja jifformalizzaw dan ftit.

190
00:07:31,730 --> 00:07:32,890
Hawnhekk huwa firxa.

191
00:07:32,890 --> 00:07:36,820
Huwa mfassal li jkun ftit
wiesgħa biss biex juru, viżwalment,

192
00:07:36,820 --> 00:07:38,920
li aħna tista 'tpoġġi kordi
fil xi ħaġa bħal din.

193
00:07:38,920 --> 00:07:41,970
U dan firxa hija
b'mod ċar mid-daqs 26 totali.

194
00:07:41,970 --> 00:07:43,935
U l-ħaġa hija msejħa
tabella arbitrarju.

195
00:07:43,935 --> 00:07:48,930
Iżda din hija biss konsenja ta 'l-artist
ta 'dak tabella hash jista' jkun.

196
00:07:48,930 --> 00:07:52,799
>> Allura tabella hash issa se
jkun struttura data livell ogħla.

197
00:07:52,799 --> 00:07:54,840
Fl-aħħar tal-ġurnata
aħna qed dwar li tara li inti

198
00:07:54,840 --> 00:07:58,700
tista 'timplimenta tabella hash, li
huwa ferm simili l-linja check-in

199
00:07:58,700 --> 00:08:02,059
fi hackathon ħafna bħal dan
tabella wżata għal issortjar kotba eżami.

200
00:08:02,059 --> 00:08:03,850
Iżda tabella hash huwa
tip ta 'dan il-livell għoli

201
00:08:03,850 --> 00:08:08,250
kunċett li tista 'tuża firxa
taħt il-barnuża biex jimplimentawha,

202
00:08:08,250 --> 00:08:11,890
jew jista 'juża lista tul, jew saħansitra
forsi xi strutturi oħra ta 'data.

203
00:08:11,890 --> 00:08:15,590
U issa li l-teħid theme--
xi wħud minn dawn l-ingredjenti fundamentali

204
00:08:15,590 --> 00:08:18,310
bħal firxa u dan il-bini
blokk issa ta 'lista tul

205
00:08:18,310 --> 00:08:21,740
u tara dak li inkella nistgħu nibnu
fuq quċċata ta 'dawk, bħal ingredjenti

206
00:08:21,740 --> 00:08:26,550
fi riċetta, jagħmlu aktar u aktar
riżultati finali interessanti u utli.

207
00:08:26,550 --> 00:08:28,680
>> Allura mat-tabella hash
nistgħu jimplimentawha

208
00:08:28,680 --> 00:08:32,540
fil-memorja pictorially bħal dan, iżda
kif jista 'attwalment jiġi kkodifikat up?

209
00:08:32,540 --> 00:08:33,789
Well, forsi bħala sempliċi hija din.

210
00:08:33,789 --> 00:08:38,270
Jekk il-kapaċità fil-tappijiet kollha, huwa biss
xi constant-- per eżempju 26,

211
00:08:38,270 --> 00:08:42,030
għal 26 ittri tal-alphabet--
I tista 'sejħa tabella varjabbli tiegħi,

212
00:08:42,030 --> 00:08:45,630
u I jista jsostnu li jien ser
tpoġġi istilel Salvelinus fil hemm, jew string.

213
00:08:45,630 --> 00:08:49,880
Allura huwa sempliċi kemm dan jekk inti
jridu jimplimentaw tabella hash.

214
00:08:49,880 --> 00:08:51,490
And yet, dan huwa verament ftit firxa.

215
00:08:51,490 --> 00:08:53,198
Iżda għal darb'oħra, a hash
tabella issa huwa dak li aħna inneħħu

216
00:08:53,198 --> 00:08:57,470
sejħa ta 'tip ta' data astratta li jinsab biss
tip ta 'saffi kunċettwali fuq nett

217
00:08:57,470 --> 00:09:00,780
ta 'xi ħaġa aktar mundane
issa tixtieq firxa.

218
00:09:00,780 --> 00:09:02,960
>> Issa, kif do we go
dwar soluzzjoni ta 'problemi?

219
00:09:02,960 --> 00:09:06,980
Well, aktar kmieni kelli l-lussu
ta 'wara spazju biżżejjed tabella hawn

220
00:09:06,980 --> 00:09:09,460
I hekk li jista 'tpoġġi l-
kwizzijiet kullimkien ridt.

221
00:09:09,460 --> 00:09:10,620
Allura Kif jista mur hawn.

222
00:09:10,620 --> 00:09:12,100
Zs jista 'jmur hawn.

223
00:09:12,100 --> 00:09:13,230
Is-Sinjura jista 'jmur hawn.

224
00:09:13,230 --> 00:09:14,740
U mbagħad I kellhom xi spazju żejjed.

225
00:09:14,740 --> 00:09:18,740
Iżda dan huwa daqsxejn ta 'iqarrqu dritt
issa għaliex din it-tabella, jekk I really

226
00:09:18,740 --> 00:09:22,720
ħsieb ta 'dan bħala firxa, huwa biss
se jkunu ta 'xi daqs fiss.

227
00:09:22,720 --> 00:09:25,380
>> Allura teknikament, jekk I iġbed
up kwizz student ħaddieħor

228
00:09:25,380 --> 00:09:28,490
u ara, oh, tal din il-persuna
isem jibda ma 'A wisq,

229
00:09:28,490 --> 00:09:30,980
I tip ta 'tixtieq li tqiegħed lilha hemmhekk.

230
00:09:30,980 --> 00:09:34,740
Imma malli I poġġih hemmhekk, jekk
din it-tabella tabilħaqq jirrappreżenta firxa,

231
00:09:34,740 --> 00:09:37,840
Jien ser tkun prevalenti jew clobbering
min kwizz dan l-istudent huwa.

232
00:09:37,840 --> 00:09:38,340
Dritt?

233
00:09:38,340 --> 00:09:41,972
Jekk dan huwa firxa, biss ħaġa waħda jista
jmorru f'kull wieħed minn dawn iċ-ċelluli jew elementi.

234
00:09:41,972 --> 00:09:43,680
U so I tip ta 'jkollhom
li pick u jagħżlu.

235
00:09:43,680 --> 00:09:45,735
>> Issa qabel I tip ta '
misruqin u ma dan jew I

236
00:09:45,735 --> 00:09:47,526
biss tip ta 'f'munzelli
minnhom hawn fuq xulxin.

237
00:09:47,526 --> 00:09:49,170
Iżda dan mhux se jtiru fil-kodiċi.

238
00:09:49,170 --> 00:09:52,260
Għalhekk, fejn jista I tpoġġi l-
istudent tieni li ismu

239
00:09:52,260 --> 00:09:54,964
huwa A jekk kollox kelli huwa dan
ispazju tabella disponibbli?

240
00:09:54,964 --> 00:09:57,880
U stajt użati tliet slots u li
Dehra hemm biss ftit oħrajn.

241
00:09:57,880 --> 00:09:58,959
Liema jista inti tagħmel?

242
00:09:58,959 --> 00:09:59,834
UDJENZA: [inaudible]

243
00:09:59,834 --> 00:10:00,565

244
00:10:00,565 --> 00:10:01,315
DAVID Malan: Yeah.

245
00:10:01,315 --> 00:10:02,370
Forsi ejja biss jżommha sempliċi.

246
00:10:02,370 --> 00:10:02,660
Dritt?

247
00:10:02,660 --> 00:10:04,243
Ma jwaħħalx fejn I tixtieq li tqiegħed lilha.

248
00:10:04,243 --> 00:10:07,450
Hekk jien ser tqiegħed lilha
teknikament fejn B tmur.

249
00:10:07,450 --> 00:10:09,932
Issa, naturalment, jien jibdew
żebgħa myself fil-kantuniera.

250
00:10:09,932 --> 00:10:11,890
Jekk niġi lil student
li ismu huwa attwalment B,

251
00:10:11,890 --> 00:10:14,840
issa B se jiġu mċaqalqa ftit
quddiem, kif jista 'jiġri, Yep,

252
00:10:14,840 --> 00:10:17,530
jekk dan huwa B, issa hija għandha tmur hawn.

253
00:10:17,530 --> 00:10:20,180
>> U hekk dan malajr ħafna
tista 'ssir problematika,

254
00:10:20,180 --> 00:10:23,850
imma hija teknika li attwalment
huwa msemmi bħala lineari probing,

255
00:10:23,850 --> 00:10:26,650
fejn inti biss tikkunsidra tiegħek
array li jkun matul il-linja.

256
00:10:26,650 --> 00:10:29,680
U inti biss tip ta 'sonda jew
jispezzjona kull element disponibbli

257
00:10:29,680 --> 00:10:31,360
tfittex għal post disponibbli.

258
00:10:31,360 --> 00:10:34,010
U hekk kif issib
waħda, inti qatra fil hemmhekk.

259
00:10:34,010 --> 00:10:38,390
>> Issa, il-prezz imħallas issa
għal din is-soluzzjoni huwa dak?

260
00:10:38,390 --> 00:10:41,300
Għandna firxa daqs fiss,
u meta I daħħal ismijiet

261
00:10:41,300 --> 00:10:44,059
fis dan, mill-inqas inizjalment, x'hemm
il running time ta 'inserzjoni

262
00:10:44,059 --> 00:10:46,350
għat-tqegħid tal-istudenti
kwizzijiet fil-bramel dritt?

263
00:10:46,350 --> 00:10:48,710

264
00:10:48,710 --> 00:10:50,002
Big O ta 'dak?

265
00:10:50,002 --> 00:10:51,147
>> UDJENZA: n.

266
00:10:51,147 --> 00:10:52,480
DAVID Malan: Smajt O kbira ta 'n.

267
00:10:52,480 --> 00:10:53,530

268
00:10:53,530 --> 00:10:54,300
Mhux veru.

269
00:10:54,300 --> 00:10:56,490
Iżda aħna ser tease apparti
għaliex fi ftit mument.

270
00:10:56,490 --> 00:10:57,702
X'iktar jista jkun?

271
00:10:57,702 --> 00:10:58,755
>> UDJENZA: [inaudible]

272
00:10:58,755 --> 00:11:00,380
DAVID Malan: U let me tagħmel dan viżwalment.

273
00:11:00,380 --> 00:11:04,720
Allura jissoponi dan huwa l-ittra S.

274
00:11:04,720 --> 00:11:05,604
>> UDJENZA: Huwa wieħed.

275
00:11:05,604 --> 00:11:06,520
DAVID Malan: Huwa wieħed.

276
00:11:06,520 --> 00:11:06,710
Dritt?

277
00:11:06,710 --> 00:11:08,950
Dan huwa firxa, li
ifisser li għandna aċċess bl-addoċċ.

278
00:11:08,950 --> 00:11:11,790
U jekk naħsbu ta 'dan
kif żero u dan bħala 25,

279
00:11:11,790 --> 00:11:13,800
u aħna tirrealizza li,
oh, hawnhekk input tiegħi S,

280
00:11:13,800 --> 00:11:16,350
I jista 'ċertament jikkonvertu
S, karattru ASCII,

281
00:11:16,350 --> 00:11:18,540
għal numru korrispondenti
bejn żero u 25

282
00:11:18,540 --> 00:11:20,910
u mbagħad minnufih
poġġih fejn jappartjeni.

283
00:11:20,910 --> 00:11:26,120
>> Iżda naturalment, malli I jiksbu l-
tieni persuna li l-isem huwa A jew B jew C

284
00:11:26,120 --> 00:11:29,300
eventwalment, jekk stajt użati l-
lineari probing bħala soluzzjoni tiegħi,

285
00:11:29,300 --> 00:11:31,360
il-ħin running ta
inserzjoni fl-agħar każ

286
00:11:31,360 --> 00:11:33,120
huwa attwalment għaddejjin biex tittrasferixxi fis liema?

287
00:11:33,120 --> 00:11:34,270

288
00:11:34,270 --> 00:11:36,045
U jien ma tismagħha hawn
korrett kmieni.

289
00:11:36,045 --> 00:11:36,920
UDJENZA: [inaudible]

290
00:11:36,920 --> 00:11:41,620
DAVID Malan: Allura huwa n tabilħaqq darba
inti għandek sett ta 'dejta kbira biżżejjed.

291
00:11:41,620 --> 00:11:44,410
Allura, min-naħa waħda, jekk
array tiegħek huwa kbir biżżejjed

292
00:11:44,410 --> 00:11:48,287
u d-data tiegħek hija skarsa biżżejjed, inti
nikseb dan iż-żmien kostanti beautiful.

293
00:11:48,287 --> 00:11:50,620
Iżda hekk kif tibda
jkollna aktar u aktar elementi,

294
00:11:50,620 --> 00:11:53,200
u biss statistikament ikollok
aktar nies bl-ittra

295
00:11:53,200 --> 00:11:56,030
A kif l-isem tagħhom jew l-ittra
B, din tista 'potenzjalment

296
00:11:56,030 --> 00:11:57,900
jiddevolvu fis xi ħaġa aktar lineari.

297
00:11:57,900 --> 00:11:59,640
Allura ma pjuttost perfetta.

298
00:11:59,640 --> 00:12:00,690
Allura nistgħu nagħmlu aħjar?

299
00:12:00,690 --> 00:12:03,210
>> Ukoll, dak li kien tagħna
Soluzzjoni qabel meta aħna

300
00:12:03,210 --> 00:12:06,820
tixtieq li jkollhom dinamiżmu aktar minn
xi ħaġa bħal firxa permessa?

301
00:12:06,820 --> 00:12:08,085

302
00:12:08,085 --> 00:12:08,960
UDJENZA: [inaudible]

303
00:12:08,960 --> 00:12:10,030
DAVID Malan: What did aħna jintroduċu?

304
00:12:10,030 --> 00:12:10,530
Yeah.

305
00:12:10,530 --> 00:12:11,430
Allura lista marbuta.

306
00:12:11,430 --> 00:12:14,430
Well, ejja ara dak marbut
lista tista 'tagħmel għalina minflok.

307
00:12:14,430 --> 00:12:17,630
Well, let me tipproponi li aħna
jiġbed l-istampa kif ġej.

308
00:12:17,630 --> 00:12:19,620
Issa dan huwa differenti
stampa minn eżempju

309
00:12:19,620 --> 00:12:24,750
minn test differenti, attwalment, li
huwa attwalment jużaw firxa ta 'daqs 31.

310
00:12:24,750 --> 00:12:28,220
U dan awtur sempliċement
iddeċieda li hash kordi

311
00:12:28,220 --> 00:12:32,430
mhux ibbażati fuq l-ismijiet tal-persuna,
iżda bbażata fuq birthdates tagħhom.

312
00:12:32,430 --> 00:12:35,680
Irrispettivament tax-xahar, huma dehret
jekk int imwieled fl-ewwel ta 'xahar

313
00:12:35,680 --> 00:12:39,580
jew il-31 ta ta 'xahar, l-awtur
se hash bbażati fuq dak il-valur,

314
00:12:39,580 --> 00:12:44,154
sabiex jinfirxu l-ismijiet out a bit
aktar milli sempliċiment 26 spots tista 'tippermetti.

315
00:12:44,154 --> 00:12:47,320
U forsi huwa ftit aktar uniformi
milli jmorru ma 'ittri alfabetiċi,

316
00:12:47,320 --> 00:12:50,236
minħabba naturalment hemm probabilment
aktar nies fid-dinja bl-ismijiet

317
00:12:50,236 --> 00:12:54,020
li tibda bil minn ċertament
xi ittri oħra tal-alfabett.

318
00:12:54,020 --> 00:12:56,380
Allura forsi dan huwa ftit
aktar uniformi, jekk wieħed jassumi

319
00:12:56,380 --> 00:12:58,640
distribuzzjoni uniformi
ta 'trabi madwar xahar.

320
00:12:58,640 --> 00:12:59,990
>> Imma, naturalment, dan għadu imperfetta.

321
00:12:59,990 --> 00:13:00,370
Dritt?

322
00:13:00,370 --> 00:13:01,370
Qed ikollna ħabtiet.

323
00:13:01,370 --> 00:13:04,680
Nies multipli f'dan
struttura tad-data għadhom

324
00:13:04,680 --> 00:13:08,432
jkollhom l-istess birthdate inqas
int irrispettivament mill xahar.

325
00:13:08,432 --> 00:13:09,640
Imma dak li l-awtur jsir?

326
00:13:09,640 --> 00:13:13,427
Ukoll, jidher qisu għandna firxa
fuq in-naħa tax-xellug mfassla vertikalment,

327
00:13:13,427 --> 00:13:15,010
iżda li biss konsenja ta 'l-artist.

328
00:13:15,010 --> 00:13:18,009
Ma jimpurtax liema direzzjoni inti
jiġbed firxa, huwa għadu firxa.

329
00:13:18,009 --> 00:13:20,225
X'inhu dan firxa ta 'apparentement?

330
00:13:20,225 --> 00:13:21,500
>> UDJENZA: lista Marbuta.

331
00:13:21,500 --> 00:13:21,650
>> DAVID Malan: Yeah.

332
00:13:21,650 --> 00:13:23,490
Jidher qisu huwa ta '
firxa ta 'lista marbuta.

333
00:13:23,490 --> 00:13:26,490
Għalhekk għal darb'oħra, dan il-punt ta 'tip
ta 'użu ta dawn l-istrutturi tad-data issa

334
00:13:26,490 --> 00:13:28,550
bħala ingredjenti għal aktar
soluzzjonijiet interessanti,

335
00:13:28,550 --> 00:13:30,862
inti tista 'assolutament tieħu
fundamentali, bħal firxa,

336
00:13:30,862 --> 00:13:33,320
u mbagħad ħu xi ħaġa aktar
interessanti bħal lista marbuta

337
00:13:33,320 --> 00:13:36,660
u anke għaqqadhom fi saħansitra
istruttura tad-data aktar interessanti.

338
00:13:36,660 --> 00:13:39,630
U fil-fatt, dan kieku wisq
jiġi msejjaħ tabella hash,

339
00:13:39,630 --> 00:13:42,610
li biha l-firxa hija
verament il-mejda hash,

340
00:13:42,610 --> 00:13:45,600
iżda dik it-tabella hash għandha
ktajjen, biex ngħidu hekk,

341
00:13:45,600 --> 00:13:50,220
li tista 'tikber jew tiċkien ibbażata fuq l-
għadd ta 'elementi li inti tixtieq li daħħal.

342
00:13:50,220 --> 00:13:52,990
>> Issa, għaldaqstant, x'hemm
il-ħin running issa?

343
00:13:52,990 --> 00:13:58,030
Jekk irrid li daħħal xi ħadd
birthday tiegħu huwa 31 Ottubru,

344
00:13:58,030 --> 00:13:59,040
fejn ma hu jew hi tmur?

345
00:13:59,040 --> 00:14:00,530

346
00:14:00,530 --> 00:14:01,030
Kull dritt.

347
00:14:01,030 --> 00:14:02,819
Fil-qiegħ nett fejn jgħid 31.

348
00:14:02,819 --> 00:14:03,610
U li perfett.

349
00:14:03,610 --> 00:14:05,060
Dan kien żmien kostanti.

350
00:14:05,060 --> 00:14:08,760
Imma x'jiġri jekk insibu xi ħadd ieħor
birthday tiegħu huwa, ejja ara,

351
00:14:08,760 --> 00:14:10,950
Ottubru, Novembru, Diċembru 31?

352
00:14:10,950 --> 00:14:12,790
Fejn hu jew hi se jmorru?

353
00:14:12,790 --> 00:14:13,290
Istess ħaġa.

354
00:14:13,290 --> 00:14:13,970
Żewġ stadji għalkemm.

355
00:14:13,970 --> 00:14:15,303
C'est kostanti għalkemm hux?

356
00:14:15,303 --> 00:14:16,360

357
00:14:16,360 --> 00:14:16,860
Kull dritt.

358
00:14:16,860 --> 00:14:17,840
Fil-mument huwa.

359
00:14:17,840 --> 00:14:20,570
Iżda fil-każ ġenerali,
L-aktar nies aħna żid,

360
00:14:20,570 --> 00:14:23,790
probabilistically, aħna qed tmur
biex jiksbu aktar u aktar kolliżjonijiet.

361
00:14:23,790 --> 00:14:26,820
>> Issa dan huwa ftit
aħjar għaliex teknikament

362
00:14:26,820 --> 00:14:34,580
issa ktajjen tiegħi jista 'jkun fil-
l-agħar każ kemm żmien?

363
00:14:34,580 --> 00:14:38,890
Jekk I daħħal n-nies fis dan aktar
istruttura tad-data sofistikati, n-nies,

364
00:14:38,890 --> 00:14:41,080
fl-agħar każ li għaddej biex tkun n.

365
00:14:41,080 --> 00:14:41,815
Għaliex?

366
00:14:41,815 --> 00:14:43,332
>> UDJENZA: Għaliex jekk kulħadd
għandu l-istess birthday,

367
00:14:43,332 --> 00:14:44,545
dawn qed tmur biex tkun linja waħda.

368
00:14:44,545 --> 00:14:45,420
DAVID Malan: Perfect.

369
00:14:45,420 --> 00:14:47,480
Jista 'jkun ftit artifiċjali,
iżda tassew fl-agħar każ,

370
00:14:47,480 --> 00:14:50,117
jekk kulħadd għandu l-istess birthday,
minħabba l-inputs ikollok,

371
00:14:50,117 --> 00:14:51,950
int se jkollhom
katina massiv twil.

372
00:14:51,950 --> 00:14:54,241
U għalhekk, inti tista 'sejħa hija ta'
hash tabella, imma verament huwa

373
00:14:54,241 --> 00:14:56,810
biss lista marbuta massiv ma
lott kollu ta 'spazju moħli.

374
00:14:56,810 --> 00:15:00,460
Iżda b'mod ġenerali, jekk nassumu li
inqas għeluq is-snin huma uniform--

375
00:15:00,460 --> 00:15:01,750
u probabbilment mhuwiex.

376
00:15:01,750 --> 00:15:02,587
Jien jagħmlu dan up.

377
00:15:02,587 --> 00:15:04,420
Imma jekk aħna nassumu, għal
l-fini ta 'diskussjoni

378
00:15:04,420 --> 00:15:07,717
li huma, imbagħad fit-teorija, jekk
dan huwa l-rappreżentazzjoni vertikali

379
00:15:07,717 --> 00:15:11,050
tal-firxa, tajjeb allura nisperaw int
se tikseb ktajjen li huma, inti taf,

380
00:15:11,050 --> 00:15:15,880
bejn wieħed u ieħor l-istess tul fejn kull waħda
dawn jirrappreżenta jum tax-xahar.

381
00:15:15,880 --> 00:15:19,930
>> Issa jekk hemm 31 jum fix-xahar,
dan ifisser running time tiegħi verament

382
00:15:19,930 --> 00:15:25,230
huwa O kbira ta 'n aktar minn 31, li
iħoss aħjar minn lineari.

383
00:15:25,230 --> 00:15:27,950
Imma dak kien wieħed ta 'tagħna
impenji ftit ġimgħat

384
00:15:27,950 --> 00:15:31,145
ilu meta ġie biex jesprimu
il running time ta 'algoriżmu?

385
00:15:31,145 --> 00:15:33,450

386
00:15:33,450 --> 00:15:35,190
Biss ħarsa biss fil-terminu ordni għolja.

387
00:15:35,190 --> 00:15:35,690
Dritt?

388
00:15:35,690 --> 00:15:37,400
31 huwa definittivament utli.

389
00:15:37,400 --> 00:15:39,610
Iżda dan għadu O kbira ta 'n.

390
00:15:39,610 --> 00:15:41,730
Iżda waħda mit-temi
ta 'problema sett ħamsa

391
00:15:41,730 --> 00:15:43,950
se jkun li
jirrikonoxxu li assolutament,

392
00:15:43,950 --> 00:15:47,320
asimptotikalment, teoretikament
din l-istruttura tad-data

393
00:15:47,320 --> 00:15:50,470
l-ebda aħjar minn sempliċiment
lista waħda enormi marbuta.

394
00:15:50,470 --> 00:15:53,550
U fil-fatt, fl-agħar każ, din
tabella hash jista jiddevolvu f'dak.

395
00:15:53,550 --> 00:15:57,620
>> Iżda fid-dinja reali, magħna bnedmin
li MACs jew PCs stess jew kwalunkwe

396
00:15:57,620 --> 00:16:01,240
u qed jitħaddmu dinja reali
software fuq data dinja reali,

397
00:16:01,240 --> 00:16:03,260
li algoritmu huma inti tmur tippreferi?

398
00:16:03,260 --> 00:16:09,180
Il-wieħed li jieħu passi finali jew li l-
wieħed li jieħu n diviż bil 31 passi

399
00:16:09,180 --> 00:16:12,900
biex isibu xi biċċa ta 'data jew
tfittex up xi informazzjoni?

400
00:16:12,900 --> 00:16:16,580
I mean, assolutament l-31 jagħmel
differenza fid-dinja reali.

401
00:16:16,580 --> 00:16:18,540
Huwa 31 darbiet aktar mgħaġġla.

402
00:16:18,540 --> 00:16:20,880
U aħna bnedmin huma ċertament
se japprezzaw li.

403
00:16:20,880 --> 00:16:23,004
>> Allura jirrealizzaw il-dikotomija
hemm bejn attwalment

404
00:16:23,004 --> 00:16:25,920
jitkellem dwar affarijiet teoretikament
u asimptotikalment li żgur

405
00:16:25,920 --> 00:16:28,760
għandu valur bħala Rajna,
iżda fid-dinja reali,

406
00:16:28,760 --> 00:16:32,930
jekk int jimpurtak biss tagħmel il-
kuntenti bniedem għal inputs ġenerali,

407
00:16:32,930 --> 00:16:36,010
inti tista 'tajjeb ħafna' tixtieq li taċċetta
il-fatt li, iva, dan huwa lineari,

408
00:16:36,010 --> 00:16:38,360
imma hija 31 darbiet aktar mgħaġġla
milli lineari jista 'jkun.

409
00:16:38,360 --> 00:16:41,610
U aħjar għadhom, aħna ma biss għandhom
tagħmel xi ħaġa arbitrarja bħal birthdate,

410
00:16:41,610 --> 00:16:44,030
nistgħu jonfqu ftit
aktar ħin u cleverness

411
00:16:44,030 --> 00:16:47,140
u jaħsbu dwar dak li nistgħu nagħmlu,
mogħti isem ta 'persuna u forsi

412
00:16:47,140 --> 00:16:50,130
birthdate tagħhom li jgħaqqdu dawk
ingredjenti biex insemmu xi ħaġa

413
00:16:50,130 --> 00:16:52,720
li hija verament aktar
uniformi u inqas jaggy,

414
00:16:52,720 --> 00:16:56,250
biex ngħidu hekk minn din l-istampa
bħalissa jissuġġerixxi li jista 'jkun.

415
00:16:56,250 --> 00:16:57,750
Kif nistgħu jimplimentaw dan fil-kodiċi?

416
00:16:57,750 --> 00:17:00,280
Well, let me tipproponi li aħna
biss tissellef xi sintassi konna

417
00:17:00,280 --> 00:17:01,799
użat koppja darbiet s'issa.

418
00:17:01,799 --> 00:17:03,590
U jien ser jiddefinixxu
node, li għal darb'oħra

419
00:17:03,590 --> 00:17:06,812
huwa terminu ġeneriku għall biss xi
kontenitur għal xi struttura tad-data.

420
00:17:06,812 --> 00:17:09,020
Jien ser tipproponi li
string huwa għaddej fil hemmhekk.

421
00:17:09,020 --> 00:17:11,369
Iżda aħna qed tmur biex jibdew jieħdu
dawk taħriġ roti off issa.

422
00:17:11,369 --> 00:17:13,230
>> Nru aktar librerija CS50
verament, jekk inti tixtieq

423
00:17:13,230 --> 00:17:15,230
jużawha għal finali tiegħek
proġett, li huwa multa,

424
00:17:15,230 --> 00:17:18,569
iżda issa aħna qed tmur biex jiġbdu lura l-
purtieri u jgħidu huwa biss stilla char.

425
00:17:18,569 --> 00:17:22,069
Allura l-kelma hemm se tkun
isem tal-persuna kkonċernata.

426
00:17:22,069 --> 00:17:25,079
U issa għandi rabta
hawn għall-node li jmiss

427
00:17:25,079 --> 00:17:28,170
sabiex dawn jirrappreżentaw
kull wieħed mill-lymph

428
00:17:28,170 --> 00:17:30,950
fil-katina, potenzjalment,
ta 'lista marbuta.

429
00:17:30,950 --> 00:17:34,090
>> U issa kif do Niddikjara
il-mejda hash innifsu?

430
00:17:34,090 --> 00:17:36,660
Kif nista niddikjara din l-istruttura sħiħa?

431
00:17:36,660 --> 00:17:40,960
Ukoll, verament, ħafna bħal I użati pointer
biss l-ewwel element ta 'lista

432
00:17:40,960 --> 00:17:44,510
qabel, b'mod simili nista biss jgħidu
I biss bżonn mazz ta 'pointers

433
00:17:44,510 --> 00:17:46,270
biex jimplimentaw din it-tabella hash kollu.

434
00:17:46,270 --> 00:17:49,484
Jien ser ikollhom firxa
sejjaħ tabella għal tabella hash.

435
00:17:49,484 --> 00:17:50,900
Li għaddej biex tkun ta 'kapaċità daqs.

436
00:17:50,900 --> 00:17:52,525
Thats kemm elementi jistgħu joqogħdu fiha.

437
00:17:52,525 --> 00:17:56,180
U kull wieħed minn dawn l-elementi f'din
array se tkun stilla node.

438
00:17:56,180 --> 00:17:56,810
Għaliex?

439
00:17:56,810 --> 00:18:00,160
Ukoll, kull din l-istampa, dak jien
implimentazzjoni tal-mejda hash bħala

440
00:18:00,160 --> 00:18:04,330
effettiv fil-bidu huwa biss
dan array li aħna ve mfassla vertikalment,

441
00:18:04,330 --> 00:18:06,820
kull wieħed li kwadri
jirrappreżenta pointer.

442
00:18:06,820 --> 00:18:09,170
Li dawk li jkollhom slashes
permezz tagħhom huma biss nulli.

443
00:18:09,170 --> 00:18:11,410
U dawk li jkollhom
vleġeġ li jmorru lejn il-lemin

444
00:18:11,410 --> 00:18:16,140
huma pointers attwali għall-lymph attwali,
għalhekk jimmiraw il-bidu ta 'lista marbuta.

445
00:18:16,140 --> 00:18:19,050
>> Allura hawnhekk, allura, huwa kif nistgħu
jimplimentaw tabella hash li

446
00:18:19,050 --> 00:18:21,580
timplimenta chaining separat.

447
00:18:21,580 --> 00:18:22,840
Issa nistgħu nagħmlu aħjar?

448
00:18:22,840 --> 00:18:25,632
Kull dritt I wiegħed aħħar darba li
nistgħu jiksbu ħin kostanti.

449
00:18:25,632 --> 00:18:27,381
U jien tip ta ħadt
ħin kostanti hawn,

450
00:18:27,381 --> 00:18:29,850
iżda mbagħad qal mhux verament
ħin kostanti għaliex huwa għadu

451
00:18:29,850 --> 00:18:31,890
dipendenti fuq it-total
numru ta 'elementi

452
00:18:31,890 --> 00:18:34,500
int inputjar fis
l-istruttura tad-data.

453
00:18:34,500 --> 00:18:35,980
Iżda jissoponi għamilna dan.

454
00:18:35,980 --> 00:18:39,550
Let me jmorru lura għall-iskrin hawn fuq.

455
00:18:39,550 --> 00:18:44,520
Let me wkoll proġettata dan up hawn, ċara
l-iskrin, u jissoponi Jien għamilt dan.

456
00:18:44,520 --> 00:18:49,300
Suppose I riedu li daħħal l-isem
Daven fil fl-istruttura tad-data tiegħi.

457
00:18:49,300 --> 00:18:52,100
>> So I tixtieq li daħħal string
Daven fl-istruttura tad-data.

458
00:18:52,100 --> 00:18:54,370
X'jiġri jekk I ma jużawx
hash tabella, iżda I użu

459
00:18:54,370 --> 00:18:56,980
xi ħaġa li l-aktar siġar simili
bħal siġra tal-familja, fejn

460
00:18:56,980 --> 00:18:59,670
ikollok xi għeruq fil-
lymph top u mbagħad u weraq

461
00:18:59,670 --> 00:19:01,440
li jmorru isfel u barra.

462
00:19:01,440 --> 00:19:04,450
Ejja ngħidu mbagħad, li jien
tixtieq li daħħal l Daven

463
00:19:04,450 --> 00:19:06,430
lejn dak li bħalissa huwa lista vojta.

464
00:19:06,430 --> 00:19:09,780
Jien ser tagħmel dan li ġej: Ninsab
se toħloq node fil din il-familja

465
00:19:09,780 --> 00:19:15,170
istruttura tad-data bħal siġra li jistenna
ftit bħal dan, li kull wieħed minnhom

466
00:19:15,170 --> 00:19:19,640
rettangoli tkun, ejja ngħidu,
għal issa 26 elementi fiha.

467
00:19:19,640 --> 00:19:21,650
U kull wieħed mill-ċelluli
f'dan array huwa għaddej

468
00:19:21,650 --> 00:19:23,470
biex jirrappreżentaw l-ittra ta 'alfabett.

469
00:19:23,470 --> 00:19:28,190
>> Speċifikament, jien ser jikkura
Din hija, imbagħad B, allura Ċ, imbagħad D,

470
00:19:28,190 --> 00:19:29,310
dan wieħed hawn.

471
00:19:29,310 --> 00:19:32,940
Allura dan se effettivament
jirrappreżentaw l-ittra D.

472
00:19:32,940 --> 00:19:36,040
Iżda biex daħħal kollha tal Daven
isem I bżonn tagħmel daqsxejn aktar.

473
00:19:36,040 --> 00:19:37,840
Hekk jien l-ewwel ser hash, biex ngħidu hekk.

474
00:19:37,840 --> 00:19:41,049
Jien ser tħares lejn l-ewwel ittra
fil Daven ta li hija ovvjament D,

475
00:19:41,049 --> 00:19:42,840
u jien ser jalloka
node li jistenna

476
00:19:42,840 --> 00:19:45,570
bħal this-- rettangolu big big
biżżejjed sabiex taqdi l-alfabett kollu.

477
00:19:45,570 --> 00:19:47,140
>> Issa D isir.

478
00:19:47,140 --> 00:19:49,720
Issa A. D-A-V-E-N huwa l-għan.

479
00:19:49,720 --> 00:19:51,220
Allura issa dak li jien ser tagħmel hu li dan.

480
00:19:51,220 --> 00:19:54,027
Hekk kif bdejt avviż D
hemm l-ebda pointer hemmhekk.

481
00:19:54,027 --> 00:19:56,860
Huwa valuri taż-żibel fil-mument,
jew I tista initialize lill nulla.

482
00:19:56,860 --> 00:19:59,630
Iżda let me iżommu għaddejjin ma
din l-idea ta 'bini ta' siġra.

483
00:19:59,630 --> 00:20:04,260
Let me jallokaw xulxin minn dawn
lymph li għandha 26-elementi fiha.

484
00:20:04,260 --> 00:20:05,150
>> U inti taf liema?

485
00:20:05,150 --> 00:20:09,130
Jekk din hija biss node fil-memorja li
I maħluqa bl malloc, bl-użu Struct

486
00:20:09,130 --> 00:20:11,240
kif aħna ser malajr tara,
Jien ser tagħmel this--

487
00:20:11,240 --> 00:20:14,450
Jien ser jiġbed vleġġa minn
il-ħaġa li tirrappreżenta D isfel

488
00:20:14,450 --> 00:20:15,860
għal dan node ġdid.

489
00:20:15,860 --> 00:20:19,240
U issa, l-ewwel il-li jmiss
ittra fl-isem Daven tal,

490
00:20:19,240 --> 00:20:24,150
V-- D-A-V-- jien ser jimxi 'l quddiem
u jiġbed node ieħor bħal dan,

491
00:20:24,150 --> 00:20:30,150
li biha, l-elementi V hawn, li
aħna ser tiġbed għall Whoops instance--.

492
00:20:30,150 --> 00:20:31,020
Aħna mhux se tiġbed hemmhekk.

493
00:20:31,020 --> 00:20:31,936
Li għaddej biex tmur hawn.

494
00:20:31,936 --> 00:20:32,890

495
00:20:32,890 --> 00:20:35,712
>> Allura aħna qed tmur biex
jqisu li dan V.

496
00:20:35,712 --> 00:20:44,920
U allura l isfel hawn aħna qed tmur biex indiċi
isfel minn V fis-dak li aħna ser jikkunsidraw E.

497
00:20:44,920 --> 00:20:50,100
U allura minn hawn aħna qed tmur biex
mur jkollhom waħda minn dawn lymph hawn.

498
00:20:50,100 --> 00:20:52,930
U issa għandna mistoqsija li jwieġbu.

499
00:20:52,930 --> 00:20:57,840
I-ħtieġa li b'xi mod jindikaw li
aħna qed fl-aħħar tas-sekwenza Daven.

500
00:20:57,840 --> 00:20:59,490
So I jistgħu biss jitilqu minnu null.

501
00:20:59,490 --> 00:21:02,670
>> Imma x'jiġri jekk għandna l Daven
isem sħiħ ukoll, li

502
00:21:02,670 --> 00:21:04,280
huwa, kif aħna stajt qal, Davenport?

503
00:21:04,280 --> 00:21:06,970
Allura dak li jekk Daven hu
attwalment substring,

504
00:21:06,970 --> 00:21:08,960
prefiss ta string ħafna itwal?

505
00:21:08,960 --> 00:21:11,450
Ma nistgħux sempliċement b'mod permanenti
jgħidu xejn huwa għaddej

506
00:21:11,450 --> 00:21:14,410
li jmorru hemm, għaliex nistgħu
qatt daħħal kelma bħal Davenport

507
00:21:14,410 --> 00:21:15,840
fis dan Struttura data

508
00:21:15,840 --> 00:21:19,560
>> Allura dak li stajna nagħmlu minflok qed
jittrattaw kull wieħed minn dawn l-elementi

509
00:21:19,560 --> 00:21:22,170
kif forsi jkollhom żewġ
Elementi ġewwa minnhom.

510
00:21:22,170 --> 00:21:24,810
Wieħed huwa pointer, tabilħaqq,
kif stajt qed tagħmel.

511
00:21:24,810 --> 00:21:27,100
Allura kull wieħed minn dawn il-kaxxi
huwa mhux biss ċellola waħda.

512
00:21:27,100 --> 00:21:29,855
Imma x'jiġri jekk il-quċċata
one-- l-waħda qiegħ tal-

513
00:21:29,855 --> 00:21:32,230
se tkun nulla, għaliex
m'hemm l-ebda Davenport għadha biss.

514
00:21:32,230 --> 00:21:34,197
X'jiġri jekk il-wieħed mill-quċċata
hija xi valur speċjali?

515
00:21:34,197 --> 00:21:36,530
U li għaddej biex tkun ftit
diffiċli biex tiġbed dan id-daqs.

516
00:21:36,530 --> 00:21:38,130
Imma jissoponi huwa biss check mark.

517
00:21:38,130 --> 00:21:38,920
Iċċekkja.

518
00:21:38,920 --> 00:21:44,230
D-A-V-E-N hija sekwenza
f'din l-istruttura tad-data.

519
00:21:44,230 --> 00:21:48,350
>> Sadanittant, jekk kelli aktar spazju
hawn, I jistgħu jagħmlu P-O-R-T,

520
00:21:48,350 --> 00:21:52,650
u I tista 'tpoġġi check fl-node
li għandha l-ittra T fl-aħħar nett.

521
00:21:52,650 --> 00:21:55,460
Allura dan huwa massiv
istruttura tad-data tħares kumplessi.

522
00:21:55,460 --> 00:21:57,210
U kalligrafija tiegħi
ċertament ma jgħinx.

523
00:21:57,210 --> 00:22:00,043
Imma jekk jien ridt li daħħal xi ħaġa
inkella, jikkunsidraw dak li nixtiequ nagħmlu.

524
00:22:00,043 --> 00:22:03,370
Jekk ridna li tpoġġi David fi,
aħna'd isegwu l-istess loġika, D-A-V,

525
00:22:03,370 --> 00:22:08,802
imma issa nirrileva fil-li jmiss
element mhux minn E, iżda minn I sa D.

526
00:22:08,802 --> 00:22:10,760
Allura hemm għaddej li jkun
aktar lymph f'dan siġra.

527
00:22:10,760 --> 00:22:12,325
Aħna qed tmur biex ikollhom malloc sejħa aktar.

528
00:22:12,325 --> 00:22:14,700
Imma jien ma jridux jagħmlu
mess kompluta ta 'din l-istampa.

529
00:22:14,700 --> 00:22:17,710
Mela ejja minflok tħares lejn wieħed
li kien ifformulat minn qabel

530
00:22:17,710 --> 00:22:21,810
bħal dan ma 'jkunx dot, dot,
tikek, iżda arrays biss abbrevjati.

531
00:22:21,810 --> 00:22:23,950
Iżda kull tal-lymph
f'dan siġra up here

532
00:22:23,950 --> 00:22:26,700
jirrappreżenta l-istess thing--
firxa Ray ta 'daqs 26.

533
00:22:26,700 --> 00:22:28,860
>> Jew jekk irridu nkunu
verament tajjeb issa, liema

534
00:22:28,860 --> 00:22:30,790
jekk l-isem ta 'xi ħadd bħala
apostrophe, ejja

535
00:22:30,790 --> 00:22:35,560
jassumi li kull node attwalment għandha
bħal 27 indiċi fiha, mhux biss 26.

536
00:22:35,560 --> 00:22:42,020
Allura dan issa se jkun data
struttura tissejjaħ trie-- T-R-I-E.

537
00:22:42,020 --> 00:22:46,120
A trie, li hija allegatament
storikament isem għaqlija għal siġra

538
00:22:46,120 --> 00:22:49,040
thats ottimizzati għal
irkupru, li naturalment,

539
00:22:49,040 --> 00:22:50,870
spjegat ma 'I-E hekk huwa trie.

540
00:22:50,870 --> 00:22:52,710
Iżda dan huwa l-istorja tal-trie.

541
00:22:52,710 --> 00:22:55,860
>> Allura trie huwa din id-data 'siġra like
struttura bħal siġra tal-familja

542
00:22:55,860 --> 00:22:57,510
li finalment iġib ruħu bħal dik.

543
00:22:57,510 --> 00:23:00,890
U hawn huwa biss eżempju ieħor ta '
mazz sħiħ ta 'ismijiet ta' nies oħrajn.

544
00:23:00,890 --> 00:23:03,540
Iżda l-kwistjoni issa
fil-idejn huwa dak ikollu

545
00:23:03,540 --> 00:23:08,070
aħna miksuba billi tintroduċi forsi aktar
istruttura tad-data ikkumplikata, u wieħed,

546
00:23:08,070 --> 00:23:09,870
franchement, li juża ħafna ta 'memorja.

547
00:23:09,870 --> 00:23:11,703
>> Għaliex anki jekk,
fil-mument, jien biss

548
00:23:11,703 --> 00:23:15,050
użu D's pointer u
A u V u Es u Ns,

549
00:23:15,050 --> 00:23:16,700
Jien ħela Heck ta lott ta 'memorja.

550
00:23:16,700 --> 00:23:18,030

551
00:23:18,030 --> 00:23:22,660
Iżda fejn I jonfqu wieħed tar-riżorsi,
I-tendenza li do jiksbu lura ieħor.

552
00:23:22,660 --> 00:23:26,020
Mela jekk jien infiq aktar spazju,
x'hemm probabbilment l-tama?

553
00:23:26,020 --> 00:23:27,407
Li jien infiq inqas liema?

554
00:23:27,407 --> 00:23:28,240
UDJENZA: Inqas ħin.

555
00:23:28,240 --> 00:23:28,990
DAVID Malan: Time.

556
00:23:28,990 --> 00:23:30,320
Issa għaliex jista 'jkun?

557
00:23:30,320 --> 00:23:33,880
Ukoll, dak li huwa l-inserzjoni
żmien, f'termini ta 'O big issa,

558
00:23:33,880 --> 00:23:37,660
ta 'isem bħal Daven
jew Davenport jew David?

559
00:23:37,660 --> 00:23:39,340
Ukoll, Daven kien ta 'ħames passi.

560
00:23:39,340 --> 00:23:42,350
Davenport ikun disa passi,
għalhekk ikun ftit aktar passi.

561
00:23:42,350 --> 00:23:44,250
David tkun ħames passi kif ukoll.

562
00:23:44,250 --> 00:23:47,230
Għalhekk dawn huma konkreti
numri, iżda żgur hemm

563
00:23:47,230 --> 00:23:49,550
rbit għoli fuq il-
tul ta 'isem ta' xi ħadd.

564
00:23:49,550 --> 00:23:52,240
U fil-fatt, fil-problema
settijiet ta 'ħames ispeċifikazzjoni,

565
00:23:52,240 --> 00:23:54,050
aħna qed tmur biex tipproponi
li huwa xi ħaġa

566
00:23:54,050 --> 00:23:55,470
li l-karattri 40-xi-fard.

567
00:23:55,470 --> 00:23:58,180
>> Realistikament, l-ebda wieħed għandu
isem infinitament twil,

568
00:23:58,180 --> 00:24:01,542
li huwa li jgħidu li t-tul ta '
isem jew it-tul ta 'sekwenza nistgħu

569
00:24:01,542 --> 00:24:03,750
ikollhom ċerti l-istat ta '
istruttura huwa probabbilment dak?

570
00:24:03,750 --> 00:24:05,550

571
00:24:05,550 --> 00:24:06,250
Huwa kostanti.

572
00:24:06,250 --> 00:24:06,430
Dritt?

573
00:24:06,430 --> 00:24:09,310
Jista 'jkun kostanti kbar bħal
40-xi ħaġa, iżda huwa kostanti.

574
00:24:09,310 --> 00:24:13,752
U għandu l-ebda dipendenza fuq kemm
ismijiet oħra huma f'din l-istruttura tad-data.

575
00:24:13,752 --> 00:24:15,460
Fi kliem ieħor, jekk I
riedu issa daħħal

576
00:24:15,460 --> 00:24:20,540
Colton jew Gabriel jew Rob jew Zamyla jew
Alison jew Belinda jew xi ismijiet oħra

577
00:24:20,540 --> 00:24:23,940
mill-persunal fis din id-data
istruttura, huwa l-ħin qed taħdem

578
00:24:23,940 --> 00:24:26,750
ta 'ddaħħal ismijiet oħra
se tkun fil-livelli kollha milquta

579
00:24:26,750 --> 00:24:30,220
mill kif ħafna elementi oħra huma
fl-istruttura tad-data diġa?

580
00:24:30,220 --> 00:24:31,040
Mhuwiex.

581
00:24:31,040 --> 00:24:31,540
Dritt?

582
00:24:31,540 --> 00:24:36,150
Għaliex aħna qed jużaw b'mod effettiv
din it-tabella hash multi-saff.

583
00:24:36,150 --> 00:24:38,280
U l-running time ta '
kwalunkwe minn dawn l-operazzjonijiet

584
00:24:38,280 --> 00:24:41,510
ma jiddependix fuq in-numru ta '
elementi li huma fl-istruttura tad-data

585
00:24:41,510 --> 00:24:43,090
jew li huma eventwalment sejrin
li jkun fl-istruttura tad-data,

586
00:24:43,090 --> 00:24:44,714
iżda fuq it-tul ta 'dak speċifikament?

587
00:24:44,714 --> 00:24:46,500

588
00:24:46,500 --> 00:24:49,200
>> L-sekwenza tkun
jiddaħħal, li ma jagħmilx

589
00:24:49,200 --> 00:24:52,580
dan asimptotikalment kostanti
O big time-- ta 'wieħed.

590
00:24:52,580 --> 00:24:54,720
U franchement, biss fil
-dinja reali, dan

591
00:24:54,720 --> 00:24:58,380
ifisser ddaħħal isem Daven iqisx
bħall-ħames passi, jew Davenport disgħa

592
00:24:58,380 --> 00:25:00,100
passi, jew David ħames passi.

593
00:25:00,100 --> 00:25:03,071
Li pjuttost darn drabi running żgħar.

594
00:25:03,071 --> 00:25:05,320
U, tabilħaqq, thats ħafna
Ħaġa tajba, speċjalment meta

595
00:25:05,320 --> 00:25:08,126
mhuwiex dipendenti fuq it-total
numru ta 'elementi fil hemmhekk.

596
00:25:08,126 --> 00:25:10,500
Allura kif tista nimplimentaw dan
tip ta 'struttura fil-kodiċi?

597
00:25:10,500 --> 00:25:12,900
Huwa ftit aktar
kumpless, iżda xorta huwa

598
00:25:12,900 --> 00:25:15,050
biss applikazzjoni ta '
blokki bażiċi tal-bini.

599
00:25:15,050 --> 00:25:17,830
Jien ser tirridefinixxi
us node kif ġej:

600
00:25:17,830 --> 00:25:21,100
BOOL sejjaħ word-- u dan
jista 'jissejjaħ xejn.

601
00:25:21,100 --> 00:25:23,970
Iżda l-BOOL tirrappreżenta
dak I ġibdet bħala marka kontroll.

602
00:25:23,970 --> 00:25:24,490
Iva.

603
00:25:24,490 --> 00:25:26,720
Dan huwa l-aħħar ta 'sekwenza
f'din l-istruttura tad-data.

604
00:25:26,720 --> 00:25:30,702
>> U, naturalment, l-istilla node
hemm qed tirreferi għat-tfal.

605
00:25:30,702 --> 00:25:32,410
U, tabilħaqq, bħad
siġra tal-familja, inti

606
00:25:32,410 --> 00:25:34,370
jikkunsidraw il-lymph
li huma mdendlin off

607
00:25:34,370 --> 00:25:36,920
tal-qiegħ ta 'xi ġenitur
element li jkun tfal.

608
00:25:36,920 --> 00:25:40,510
U għalhekk it-tfal se
tkun firxa ta '27, is-27 wieħed

609
00:25:40,510 --> 00:25:41,680
biss qed għall apostrophe.

610
00:25:41,680 --> 00:25:43,390
Aħna qed tmur biex issolvi
ta 'każ speċjali li.

611
00:25:43,390 --> 00:25:45,400
Allura inti jista 'jkollhom ċerta
ismijiet bil apostrophes.

612
00:25:45,400 --> 00:25:47,399
Forsi anke sing suppost
jmorru fil hemm, iżda inti ser

613
00:25:47,399 --> 00:25:50,330
tara fil-sett p 5 aħna biss kura
dwar ittri u apostrophes.

614
00:25:50,330 --> 00:25:52,990
>> U allura kif do inti tirrappreżenta
l-istruttura tad-data nnifisha?

615
00:25:52,990 --> 00:25:56,454
Kif taħseb li tirrappreżenta l-għerq
ta 'dan trie, biex ngħidu hekk?

616
00:25:56,454 --> 00:25:59,620
Ukoll, Eżatt bħal ma 'lista marbuta, inti
bżonn ta 'pointer li l-ewwel element.

617
00:25:59,620 --> 00:26:04,270
Bil trie inti biss bżonn waħda
pointer li l-għerq ta 'din trie.

618
00:26:04,270 --> 00:26:07,290
U minn hemm inti tista hash
tiegħek mod isfel aktar profonda u aktar profonda

619
00:26:07,290 --> 00:26:10,460
għal kull node oħra fl-istruttura.

620
00:26:10,460 --> 00:26:13,440
Allura sempliċiment ma dan jista
aħna nirrappreżentaw li Struct.

621
00:26:13,440 --> 00:26:15,877
>> Issa Meanwhile-- Oh, kwistjoni.

622
00:26:15,877 --> 00:26:17,220
>> UDJENZA: X'hemm kelma BOOL?

623
00:26:17,220 --> 00:26:20,490
>> DAVID Malan: kelma BOOL huwa
biss dan Inkarnazzjoni C

624
00:26:20,490 --> 00:26:22,920
ta 'dak I deskritt
f'din il-kaxxa hawn, meta

625
00:26:22,920 --> 00:26:26,000
I bdew inqasmu kull wieħed mill-
Elementi array f'żewġ biċċiet.

626
00:26:26,000 --> 00:26:27,600
Wieħed huwa pointer għall-node li jmiss.

627
00:26:27,600 --> 00:26:30,280
L-oħra għandha tkun
xi ħaġa bħal kaxxa kontroll

628
00:26:30,280 --> 00:26:33,770
biex ngħid iva, hemm
kelma Daven li tispiċċa hawnhekk,

629
00:26:33,770 --> 00:26:35,610
għaliex aħna ma rridux,
fil-mument, Dave.

630
00:26:35,610 --> 00:26:39,320
>> Anki jekk Dave se jkun
kelma leġittimu, huwa ma fil-trie

631
00:26:39,320 --> 00:26:39,830
s'issa.

632
00:26:39,830 --> 00:26:40,950
U D mhijiex kelma.

633
00:26:40,950 --> 00:26:42,770
U D-A mhijiex kelma jew isem.

634
00:26:42,770 --> 00:26:45,020
Allura l-check mark
jindika biss ladarba inti

635
00:26:45,020 --> 00:26:48,190
hit dan node huwa l-
passaġġ preċedenti ta 'karattri

636
00:26:48,190 --> 00:26:50,700
attwalment string li inti stajt mdaħħal.

637
00:26:50,700 --> 00:26:53,660
Allura li kollox l-BOOL
hemm qed tagħmel għalina.

638
00:26:53,660 --> 00:26:55,500
>> Kwalunkwe mistoqsijiet oħra fuq tipprova?

639
00:26:55,500 --> 00:26:56,215
Yeah.

640
00:26:56,215 --> 00:26:58,035
>> UDJENZA: X'inhu l-overlap?

641
00:26:58,035 --> 00:26:59,945
X'jiġri jekk għandek Dave u Daven?

642
00:26:59,945 --> 00:27:00,820
DAVID Malan: Perfect.

643
00:27:00,820 --> 00:27:02,580
X'jiġri jekk għandek Dave u Daven?

644
00:27:02,580 --> 00:27:06,240
Hekk jekk aħna daħħal, ngħidu nickname,
għall David-- Dave-- D-A-V-E?

645
00:27:06,240 --> 00:27:07,370

646
00:27:07,370 --> 00:27:08,700
Dan huwa attwalment sempliċi super.

647
00:27:08,700 --> 00:27:10,325
Allura aħna qed biss ser jieħdu erba 'passi.

648
00:27:10,325 --> 00:27:11,042

649
00:27:11,042 --> 00:27:15,847
D-A-V-E. U dak li għandi biex
tagħmel darba I hit li r-raba node?

650
00:27:15,847 --> 00:27:16,680
Biss jmorru biex jiċċekkjaw.

651
00:27:16,680 --> 00:27:18,000
Aħna diġà tajba biex tmur.

652
00:27:18,000 --> 00:27:18,840
Isir.

653
00:27:18,840 --> 00:27:19,750
Erba 'passi.

654
00:27:19,750 --> 00:27:21,590
Ta 'żmien kostanti asimptotikalment.

655
00:27:21,590 --> 00:27:26,300
U issa konna indikat li kemm Dave
u Daven huma kordi fl-istruttura.

656
00:27:26,300 --> 00:27:27,710
Allura mhux problema.

657
00:27:27,710 --> 00:27:30,200
U avviż kif il-preżenza
ta Daven ma jagħmluhiex

658
00:27:30,200 --> 00:27:34,750
tieħu kwalunkwe aktar ħin jew inqas
żmien għall Dave u viċi versa.

659
00:27:34,750 --> 00:27:36,000
>> Allura dak li inkella nistgħu issa tagħmel?

660
00:27:36,000 --> 00:27:40,680
Imxejna użat dan metafora qabel
ta 'dixxijiet jirrappreżentaw xi ħaġa.

661
00:27:40,680 --> 00:27:43,380
Iżda jirriżulta li l-
munzell ta 'dixxijiet huwa attwalment

662
00:27:43,380 --> 00:27:47,187
dimostrattiva tad-data ieħor astratt
type-- data struttura livell ogħla

663
00:27:47,187 --> 00:27:49,770
li fl-aħħar il-jum huwa biss
bħal firxa jew lista marbuta

664
00:27:49,770 --> 00:27:50,970
jew xi ħaġa aktar mundane.

665
00:27:50,970 --> 00:27:53,270
Imma hija aktar interessanti
kunċett kunċettwali.

666
00:27:53,270 --> 00:27:56,440
A munzell, bħal dawn
trejs hawn fil Mather,

667
00:27:56,440 --> 00:27:58,750
huma ġeneralment jissejħu
biss that-- munzell.

668
00:27:58,750 --> 00:28:02,540
>> U f'dan it-tip ta 'struttura data
għandek żewġ operations--

669
00:28:02,540 --> 00:28:05,880
għandek wieħed imsejjaħ push għal
żżid xi ħaġa li l-munzell,

670
00:28:05,880 --> 00:28:08,320
bħal tqegħid trej ieħor
Lura fuq il-quċċata tal-munzell.

671
00:28:08,320 --> 00:28:11,350
U mbagħad pop, li jfisser li inti
jieħdu l-topmost off trej.

672
00:28:11,350 --> 00:28:16,210
Imma x'hemm ewlieni dwar munzell hu li
huwa ltqajna din il-karatteristika kurjuż.

673
00:28:16,210 --> 00:28:19,560
Peress li l-persunal dining sala huma
titranġa l-trejs għall-ikla li jmiss,

674
00:28:19,560 --> 00:28:21,380
dak li għaddej biex tkun
vera dwar kif l-istudenti

675
00:28:21,380 --> 00:28:22,856
jinteraġixxu ma 'din l-istruttura tad-data?

676
00:28:22,856 --> 00:28:24,480
UDJENZA: Huma qed tmur biex pop off wieħed.

677
00:28:24,480 --> 00:28:26,550
DAVID Malan: Huma qed tmur biex
pop off waħda, nisperaw il-quċċata.

678
00:28:26,550 --> 00:28:28,910
Inkella huwa biss tip ta 'stupid
li jmorru it-triq kollha lejn il-qiegħ.

679
00:28:28,910 --> 00:28:29,070
Dritt?

680
00:28:29,070 --> 00:28:31,620
L-istruttura tad-data ma verament jippermettu
inti grab-trej qiegħ inqas

681
00:28:31,620 --> 00:28:32,520
faċilment.

682
00:28:32,520 --> 00:28:35,040
Allura hemm dan kurjuż
proprjetà lil munzell

683
00:28:35,040 --> 00:28:39,730
li l-aħħar oġġett fil hija
se tkun l-ewwel wieħed out.

684
00:28:39,730 --> 00:28:43,400
U xjenzjati tal-kompjuter sejħa
dan LIFO-- aħħar fl-ewwel out.

685
00:28:43,400 --> 00:28:45,540
U fil-fatt ma jkollu
applikazzjonijiet interessanti.

686
00:28:45,540 --> 00:28:50,090
Mhuwiex neċessarjament bħala ovvju kif xi wħud
oħrajn, iżda tista ', tabilħaqq, ikun utli,

687
00:28:50,090 --> 00:28:54,040
u tista ', tabilħaqq, jiġi implimentat
fi ftit ta 'modi differenti.

688
00:28:54,040 --> 00:28:58,550
>> Allura wieħed, u fil-fatt, let
me ma adsa fis dan.

689
00:28:58,550 --> 00:28:59,860
Ejja nagħmlu dan minflok.

690
00:28:59,860 --> 00:29:03,700
Ejja nħarsu lejn wieħed li kważi l-
istess idea, imma hija aktar ġust ftit.

691
00:29:03,700 --> 00:29:04,200
Dritt?

692
00:29:04,200 --> 00:29:07,560
Jekk int wieħed minn dawn subien fann jew
bniet li verament jħobb prodotti Apple

693
00:29:07,560 --> 00:29:10,130
u inti woke up fil 03:00
għal-linja up f'xi maħżen

694
00:29:10,130 --> 00:29:14,150
biex tikseb l-aħħar ħafna iPhone, inti
jista 'jkollhom fil-kju up bħal dan.

695
00:29:14,150 --> 00:29:15,800
>> Issa kju hija deliberatament ħafna jismu.

696
00:29:15,800 --> 00:29:18,190
Huwa linja għaliex hemm
xi ġustizzja miegħu.

697
00:29:18,190 --> 00:29:18,690
Dritt?

698
00:29:18,690 --> 00:29:21,690
Ikun tip ta mirdugħa jekk inti stajt
ltqajna hemm l-ewwel fil-Aħżen Apple

699
00:29:21,690 --> 00:29:25,700
imma inti effettivament l-bottommost
trej minħabba li l-impjegati Apple allura

700
00:29:25,700 --> 00:29:28,189
pop l-aħħar persuna li
attwalment marret fil-linja.

701
00:29:28,189 --> 00:29:31,230
Allura stacks u kjuwijiet, anke jekk
funzjonalment dawn qed tip ta 'l-same--

702
00:29:31,230 --> 00:29:33,105
huwa biss dan il-ġbir
ta 'riżorsi li l-

703
00:29:33,105 --> 00:29:36,210
hemm għaddej biex jikbru u shrink-- s
dan l-aspett ġustizzja miegħu,

704
00:29:36,210 --> 00:29:39,634
inqas fid-dinja reali,
fejn l-operazzjonijiet inti eżerċizzju

705
00:29:39,634 --> 00:29:40,800
huma fundamentalment differenti.

706
00:29:40,800 --> 00:29:43,360
A stack-- kju
rather-- huwa qal li jkollhom

707
00:29:43,360 --> 00:29:45,320
żewġ operazzjonijiet: kju n u d kju.

708
00:29:45,320 --> 00:29:46,341

709
00:29:46,341 --> 00:29:48,090
Jew tista 'sejħa lilhom
kwalunkwe numru ta 'affarijiet.

710
00:29:48,090 --> 00:29:50,770
Imma inti biss tixtieq li jaqbdu
l-idea li wieħed qed iżżid

711
00:29:50,770 --> 00:29:53,230
u wieħed huwa finalment jitnaqqas.

712
00:29:53,230 --> 00:29:58,840
>> Issa taħt il-barnuża, kemm il-munzell
u kju jista 'jiġi implimentat kif?

713
00:29:58,840 --> 00:30:01,390
Aħna mhux se jmorru fil-kodiċi ta '
minħabba li l-livell ogħla

714
00:30:01,390 --> 00:30:03,387
idea hija tip ta 'aktar ovvji.

715
00:30:03,387 --> 00:30:04,470
I mean, liema do bnedmin do?

716
00:30:04,470 --> 00:30:07,030
Jekk jien l-ewwel persuna fil-Apple
Jaħżnu u dan huwa l-bieb ta 'quddiem,

717
00:30:07,030 --> 00:30:08,130
tafu, jien ser toqgħod hawn.

718
00:30:08,130 --> 00:30:09,750
U l-persuna li jmiss
tmur toqgħod hawn.

719
00:30:09,750 --> 00:30:11,500
U l-persuna li jmiss
tmur toqgħod hawn.

720
00:30:11,500 --> 00:30:13,792
Allura dak struttura tad-data
jippresta ruħu għal kju?

721
00:30:13,792 --> 00:30:14,542
>> UDJENZA: A kju.

722
00:30:14,542 --> 00:30:15,667
DAVID Malan: Well, kju.

723
00:30:15,667 --> 00:30:16,390
Sure.

724
00:30:16,390 --> 00:30:16,920
X'iktar?

725
00:30:16,920 --> 00:30:17,600
>> UDJENZA: Lista marbuta.

726
00:30:17,600 --> 00:30:18,990
>> DAVID Malan: A marbuta
lista inti jista 'jimplimenta.

727
00:30:18,990 --> 00:30:22,500
U lista marbuta huwa sbieħ għaliex imbagħad
li tista 'tikber arbitrarjament twil kif oppost

728
00:30:22,500 --> 00:30:24,880
li jkollhom xi numru fiss
ta 'nies fil-maħżen.

729
00:30:24,880 --> 00:30:27,030
Imma forsi numru fiss
ta 'postijiet huwa leġittimu.

730
00:30:27,030 --> 00:30:30,350
Għaliex jekk għandhom biss bħal 20
iPhones fl-ewwel jum, forsi

731
00:30:30,350 --> 00:30:33,930
huma jeħtieġu biss firxa ta 'daqs
20 biex jirrappreżenta dak kju, li

732
00:30:33,930 --> 00:30:37,070
huwa biss ngħid issa ladarba nibdew nitkellmu
dwar dawn il-problemi ta 'livell ogħla,

733
00:30:37,070 --> 00:30:38,890
inti tista jimplimentawha
fi kwalunkwe numru ta 'modi.

734
00:30:38,890 --> 00:30:42,030
U hemm probabbilment biss se
tkun kummerċ off fl-ispazju u l-ħin

735
00:30:42,030 --> 00:30:43,950
jew biss fil-kodiċi kumplessità tiegħek stess.

736
00:30:43,950 --> 00:30:45,380
>> What about munzell?

737
00:30:45,380 --> 00:30:48,190
Ukoll, munzell, Rajna wisq
jista 'jkun biss dawn trejs.

738
00:30:48,190 --> 00:30:50,007
U inti tista 'timplimenta din firxa.

739
00:30:50,007 --> 00:30:53,090
Iżda f'xi punt jekk inti tuża firxa,
x'inhu jiġri lill-trejs

740
00:30:53,090 --> 00:30:54,173
inti qed tipprova li jħott?

741
00:30:54,173 --> 00:30:55,170

742
00:30:55,170 --> 00:30:55,670
Kull dritt.

743
00:30:55,670 --> 00:30:57,490
Int biss ser
ikunu jistgħu jmorru daqshekk għolja.

744
00:30:57,490 --> 00:31:00,156
U naħseb fil Mather li qed
attwalment minquxa f'dak ftuħ.

745
00:31:00,156 --> 00:31:01,950
Allura fil-fatt, huwa kważi
bħall Mather qed tuża

746
00:31:01,950 --> 00:31:03,783
firxa ta 'daqs fiss,
għaliex inti tista 'biss

747
00:31:03,783 --> 00:31:08,302
tajbin tant trejs f'dak ftuħ
il-ħajt stabbiliti hawn taħt irkopptejn tan-nies.

748
00:31:08,302 --> 00:31:10,010
U hekk li jista 'jkun
qal li jkun firxa,

749
00:31:10,010 --> 00:31:14,300
imma nistgħu ċertament jimplimentaw dik
b'mod aktar ġenerali ma 'lista marbuta.

750
00:31:14,300 --> 00:31:16,390
>> Ukoll, dak dwar l-istruttura tad-data ieħor?

751
00:31:16,390 --> 00:31:18,760
Let me pull up wieħed ieħor viżwali hawn.

752
00:31:18,760 --> 00:31:24,710
Xi ħaġa simili kif dwar dan wieħed hawn?

753
00:31:24,710 --> 00:31:28,920
Għaliex jista 'dan ikun utli li jkun hemm ma
xi ħaġa bħala fancy bħala trie, li

754
00:31:28,920 --> 00:31:32,370
aħna raw kellhom dawn lymph wiesgħa ħafna,
kull wieħed minnhom huwa fil-firxa?

755
00:31:32,370 --> 00:31:35,740
Imma x'jiġri jekk nagħmlu xi ħaġa aktar
sempliċement, bħal siġra tal-familja iskola antika,

756
00:31:35,740 --> 00:31:38,110
kull wieħed li lymph hawn
huwa biss ħażna numru.

757
00:31:38,110 --> 00:31:42,180
Minflok ta 'isem jew dixxendent
huwa biss ħażna numru bħal dan.

758
00:31:42,180 --> 00:31:45,250
>> Ukoll, il-jargon nużaw fil
strutturi ta 'dejta huwa kemm jipprova

759
00:31:45,250 --> 00:31:49,510
u siġar, fejn trie, għal darb'oħra, huwa
wieħed li l lymph huma arrays biss,

760
00:31:49,510 --> 00:31:51,680
għadu dak li inti tista '
jużaw mill-iskola grad

761
00:31:51,680 --> 00:31:53,860
meta inti ssir familjari
weraq tree-- u l-għerq

762
00:31:53,860 --> 00:31:57,250
tas-siġra u t-tfal ta 'l-
ġenitur u aħwa tiegħu.

763
00:31:57,250 --> 00:32:03,670
U aħna tista 'timplimenta siġra,
per eżempju, bħala sempliċement bħala dan.

764
00:32:03,670 --> 00:32:07,420
A siġra, jekk bħala node, wieħed mill
dawn ċrieki li għandha numru,

765
00:32:07,420 --> 00:32:09,947
mhuwiex ser ikollhom
wieħed pointer, iżda tnejn.

766
00:32:09,947 --> 00:32:11,780
U hekk kif inti żid
tieni pointer, inti

767
00:32:11,780 --> 00:32:13,905
jistgħu attwalment issa jagħmlu sort
ta 'data żewġ dimensjonijiet

768
00:32:13,905 --> 00:32:14,780
strutturi fil-memorja.

769
00:32:14,780 --> 00:32:16,660
Ħafna bħal żewġ dimensjonijiet
array, inti tista

770
00:32:16,660 --> 00:32:18,904
jkollhom tip ta 'żewġ dimensjonijiet
listi marbuta iżda dawk

771
00:32:18,904 --> 00:32:20,820
li jsegwu mudell
fejn hemm l-ebda ċikli.

772
00:32:20,820 --> 00:32:24,487
Huwa verament siġra ma 'wieħed
mod nanniet up hawn u mbagħad

773
00:32:24,487 --> 00:32:27,320
xi ġenituri u t-tfal u
neputijiet u great-neputijiet.

774
00:32:27,320 --> 00:32:28,370
u ibqa 'sejjer hekk.

775
00:32:28,370 --> 00:32:32,390
>> Imma x'hemm verament pulita dwar dan ukoll,
biss biex tease inti ma 'ftit ta' kodiċi,

776
00:32:32,390 --> 00:32:35,370
recursion irtirar minn
awhile lura, fejn

777
00:32:35,370 --> 00:32:38,220
tikteb funzjoni li s-sejħiet innifsu.

778
00:32:38,220 --> 00:32:41,140
Din hija opportunità sabiħa
biex jimplimentaw xi ħaġa

779
00:32:41,140 --> 00:32:42,920
bħal recursion, għaliex jikkunsidraw dan.

780
00:32:42,920 --> 00:32:43,860
>> Din hija siġra.

781
00:32:43,860 --> 00:32:48,040
U stajt kien anali ftit mal-mod kif
I tpoġġi l-interi fit-triq.

782
00:32:48,040 --> 00:32:51,020
Tant li hija għandha speċjali
name-- siġra tfittxija binarja.

783
00:32:51,020 --> 00:32:53,460
Issa aħna widnejna binarja
tfittxija, imma tista 'inti

784
00:32:53,460 --> 00:32:55,180
xogħol b'lura mill-isem dan ħaġa l-?

785
00:32:55,180 --> 00:32:59,280
X'inhu l-mudell ta 'kif I
mdaħħla l-interi fis din is-siġra?

786
00:32:59,280 --> 00:33:00,696
Mhuwiex arbitrarja.

787
00:33:00,696 --> 00:33:01,570
Hemm xi mudell.

788
00:33:01,570 --> 00:33:02,090
Yeah.

789
00:33:02,090 --> 00:33:03,370
>> UDJENZA: dawk iżgħar fuq ix-xellug.

790
00:33:03,370 --> 00:33:03,690
>> DAVID Malan: Yeah.

791
00:33:03,690 --> 00:33:05,062
Dawk iżgħar huma fuq ix-xellug.

792
00:33:05,062 --> 00:33:06,270
Oħrajn akbar huma fuq il-lemin.

793
00:33:06,270 --> 00:33:12,940
Tali li dikjarazzjoni vera hija
ġenitur huwa akbar minn tifel xellug tagħha,

794
00:33:12,940 --> 00:33:14,850
iżda inqas minn wild dritt tagħha.

795
00:33:14,850 --> 00:33:17,750
U li waħdu huwa saħansitra
definizzjoni verbali rikursivi

796
00:33:17,750 --> 00:33:20,500
għaliex inti tista 'tapplika dak
istess loġika għal kull node

797
00:33:20,500 --> 00:33:23,080
u biss qigħan
out, f'każ bażiku jekk inti

798
00:33:23,080 --> 00:33:25,740
se, meta inti hit waħda
il-weraq, biex ngħidu hekk,

799
00:33:25,740 --> 00:33:28,580
fejn leave m'għandha l-ebda tfal aktar.

800
00:33:28,580 --> 00:33:30,614
>> Issa kif tista 'issib l-għadd 44?

801
00:33:30,614 --> 00:33:32,280
Inti tibda fil-għerq u jgħidu, hm.

802
00:33:32,280 --> 00:33:35,690
55 mhuwiex 44 So do Irrid immur
dritt jew għandi tixtieq li tmur xellug?

803
00:33:35,690 --> 00:33:37,190
Well, ovvjament inti tixtieq li tmur xellug.

804
00:33:37,190 --> 00:33:40,060
U hekk huwa bħad-telefon
Eżempju ktieb fit-tfittxija binarja

805
00:33:40,060 --> 00:33:41,099
b'mod aktar ġenerali.

806
00:33:41,099 --> 00:33:43,390
Iżda aħna qed jimplimentawh
issa ftit aktar dinamiku

807
00:33:43,390 --> 00:33:45,339
minn firxa tista 'tippermetti.

808
00:33:45,339 --> 00:33:48,130
U fil-fatt, jekk inti trid tfittex
lejn il-kodiċi, ewwel daqqa t'għajn żgur.

809
00:33:48,130 --> 00:33:49,671
Jidher qisu mazz sħiħ ta 'linji.

810
00:33:49,671 --> 00:33:51,220
Iżda huwa beautifully sempliċi.

811
00:33:51,220 --> 00:33:54,490
Jekk inti tixtieq li jimplimentaw funzjoni
imsejħa tfittxija li l-iskop fil-ħajja

812
00:33:54,490 --> 00:33:57,290
huwa ta 'tiftix għal valur
bħal n, integer,

813
00:33:57,290 --> 00:34:01,756
u int għadda fi pointer-- wieħed
pointer għall-node ta 'l-għeruq,

814
00:34:01,756 --> 00:34:04,380
pjuttost, ta 'dak siġra li minnha
inti tista 'aċċess kollox,

815
00:34:04,380 --> 00:34:08,850
avviż kif jinftiehem
inti tista 'timplimenta l-loġika.

816
00:34:08,850 --> 00:34:10,880
Jekk siġra huwa null,
ovvjament mhuwiex hemmhekk.

817
00:34:10,880 --> 00:34:11,880
Ejja biss ritorn foloz.

818
00:34:11,880 --> 00:34:12,000
Dritt?

819
00:34:12,000 --> 00:34:14,040
Jekk inti jagħtih xejn,
hemm xejn hemmhekk.

820
00:34:14,040 --> 00:34:17,900
>> Inkella, jekk n hija inqas minn
vleġġa siġra n-- issa vleġġa n,

821
00:34:17,900 --> 00:34:20,670
recall aħna introdotti super
qosor l-oħra jum,

822
00:34:20,670 --> 00:34:25,100
u li biss ifisser de-referenza tal-
pointer u ħarsa lejn il-qasam imsejħa n.

823
00:34:25,100 --> 00:34:27,690
Allura dan ifisser jmorru hemm u
tħares lejn il-qasam imsejħa n.

824
00:34:27,690 --> 00:34:33,810
Hekk jekk n, il-valur int tingħata, hija inqas
mill-valur fil-numru sħiħ siġar,

825
00:34:33,810 --> 00:34:35,449
fejn do inti tixtieq li tmur?

826
00:34:35,449 --> 00:34:36,389
Lejn ix-xellug.

827
00:34:36,389 --> 00:34:37,780
>> Allura avviż-recursion.

828
00:34:37,780 --> 00:34:39,860
Jien returning-- mhux veru.

829
00:34:39,860 --> 00:34:40,989
Mhux falza.

830
00:34:40,989 --> 00:34:45,670
Jien jirritornaw x'ikun ir-risposta
huwa minn sejħa għal myself, li jgħaddi

831
00:34:45,670 --> 00:34:50,100
n darb'oħra, li huwa żejjed,
imma dak kemmxejn differenti issa?

832
00:34:50,100 --> 00:34:51,989
Kif am I jagħmlu l-problema iżgħar?

833
00:34:51,989 --> 00:34:54,920
Jien tgħaddi fit bħala t-tieni
argument, mhux l-għerq tal-siġra,

834
00:34:54,920 --> 00:34:59,616
iżda l-wild xellug f'dan il-każ.

835
00:34:59,616 --> 00:35:00,990
Hekk jien tgħaddi fil-wild xellug.

836
00:35:00,990 --> 00:35:04,720
>> Sadanittant, jekk n hija akbar minn
l-node jien bħalissa tħares lejn,

837
00:35:04,720 --> 00:35:06,690
I tfittex il-lemin.

838
00:35:06,690 --> 00:35:10,880
Inkella, jekk l-siġra ma huwiex null, u
jekk l-element mhuwiex lejn ix-xellug

839
00:35:10,880 --> 00:35:13,240
u mhuwiex għad-dritt,
dak li huwa wonderfully il-każ?

840
00:35:13,240 --> 00:35:14,630

841
00:35:14,630 --> 00:35:18,440
Imxejna attwalment jinstabu l-node fil
kwistjoni, u għalhekk nerġgħu lura veru.

842
00:35:18,440 --> 00:35:21,490
>> Allura aħna ħadthom biss scratched-wiċċ
issa xi wħud minn dawn l-istrutturi tad-data.

843
00:35:21,490 --> 00:35:24,370
Fil problema sett ħamsa tkun taf
jesploraw dawn għadhom ulterjuri,

844
00:35:24,370 --> 00:35:27,250
u tkun taf tkun tingħata disinn tiegħek
għażla ta 'kif imorru dwar dan.

845
00:35:27,250 --> 00:35:30,250
What I tixtieq li jikkonkludu fuq
huwa biss 30 sekonda teaser

846
00:35:30,250 --> 00:35:32,080
ta 'dak li jistenna ġimgħa d-dieħla u lil hinn.

847
00:35:32,080 --> 00:35:35,390
>> Kif aħna begin-- Thankfully inti tista
think-- transizzjoni tagħna bil-mod

848
00:35:35,390 --> 00:35:38,680
mid-dinja ta 'C u t'isfel
dettalji tal-implimentazzjoni livell,

849
00:35:38,680 --> 00:35:42,090
għal dinja li nistgħu tieħu għall
mogħti li xi ħadd ieħor ħa finalment

850
00:35:42,090 --> 00:35:44,010
din id-dejta implimentati
strutturi għalina,

851
00:35:44,010 --> 00:35:47,570
u aħna ser tibda biex jifhmu l-
dinja reali mezzi ta 'implimentazzjoni

852
00:35:47,570 --> 00:35:50,560
programmi fuq l-internet u
websajts aktar ġenerali

853
00:35:50,560 --> 00:35:52,910
u wkoll is-sigurtà ħafna
implikazzjonijiet li Imxejna biss

854
00:35:52,910 --> 00:35:54,850
bdew tobrox il-wiċċ ta '.

855
00:35:54,850 --> 00:35:57,320
Hawnhekk huwa dak li jistenna us
fil-jiem li ġejjin.

856
00:35:57,320 --> 00:36:00,480
>> [Daqq ta 'video]

857
00:36:00,480 --> 00:36:03,432

858
00:36:03,432 --> 00:36:12,780
>> -He Daħal bil-messaġġ,
bi protokoll kollu tiegħu stess.

859
00:36:12,780 --> 00:36:26,110

860
00:36:26,110 --> 00:36:30,894
Huwa daħal għal dinja ta krudili
firewalls, routers uncaring,

861
00:36:30,894 --> 00:36:33,368
u l-perikli ferm agħar milli mewt.

862
00:36:33,368 --> 00:36:35,280

863
00:36:35,280 --> 00:36:36,236
Hu mgħaġġel.

864
00:36:36,236 --> 00:36:37,980
Hu b'saħħtu.

865
00:36:37,980 --> 00:36:42,830
Hu TCP / IP, u hu ltqajna l-indirizz tiegħek.

866
00:36:42,830 --> 00:36:45,290

867
00:36:45,290 --> 00:36:48,074
"ġellieda tal-Net."

868
00:36:48,074 --> 00:36:49,660
[END daqq ta 'video]

869
00:36:49,660 --> 00:36:50,910
DAVID Malan: Niġu ġimgħa d-dieħla.

870
00:36:50,910 --> 00:36:51,880
Aħna se tara inti mbagħad.

871
00:36:51,880 --> 00:36:54,615

872
00:36:54,615 --> 00:36:56,060
[Daqq ta 'video]

873
00:36:56,060 --> 00:36:59,240
-u Issa, "Ħsibijiet Deep"
billi Daven Farnham.

874
00:36:59,240 --> 00:37:02,030

875
00:37:02,030 --> 00:37:05,820
-David Dejjem jibda
lectures ma, "Kull dritt."

876
00:37:05,820 --> 00:37:08,750
Għaliex ma, "Hawn is-soluzzjoni
għal sett problema din il-ġimgħa "

877
00:37:08,750 --> 00:37:12,180
jew "Aħna qed tagħti kollha inti A?"

878
00:37:12,180 --> 00:37:13,380
[Laughing]

879
00:37:13,380 --> 00:37:15,530
[END daqq ta 'video]