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>> [Music kucheza]

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>> Rob BOWDEN: Ni mimi, Rob.

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Hebu kutembea kwa njia ya jinsi ya
kutekeleza Mario.

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Hivyo jambo la kwanza tunahitaji kufanya ni
haraka user ajili ya pembejeo.

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>> Tunahitaji kuwauliza ni jinsi gani
mrefu piramidi lazima.

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Hivyo hapa, tunaona sisi ni kufanya
urefu = GetInt.

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Na kukumbuka kwamba kazi GetInt
unatekelezwa katika CS50

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maktaba, hivyo juu juu, tunahitaji
kumbuka # ni pamoja na cs50.h.

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>> Hivyo kwa nini tuna hii amefungwa
katika do-kitanzi wakati?

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Naam, sisi pia haja ya kukumbuka kuwa
pembejeo mtumiaji ina kuwa halali.

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Ni pembejeo batili nini?

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Vizuri pset spec hasa anasema
kwamba urefu chini ya 0 au zaidi

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zaidi ya 23 ni batili.

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>> Hivyo hapa, tunaona kwamba sisi ni kufafanua
mara kwa mara aitwaye MAX_HEIGHT na

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thamani ya 23.

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Hii kitanzi do-wakati itaendelea wakati
urefu ni chini ya 0 au MAX_HEIGHT ni

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chini ya urefu, ambayo ina maana kwamba
23 ni chini ya urefu.

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Hivyo kama urefu ni 24 au zaidi, sisi ni
kwenda kuendelea wanaoendesha.

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Kumbuka kwamba kufanya-wakati tanzi ni pretty
kusaidia wakati wowote tunataka kupata

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user pembejeo na kisha kuhalalisha yake, tangu
sisi inevitably haja ya kuuliza user katika

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angalau mara moja kwa thamani wanataka.

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>> Hivyo mara tuna mchango wao, sisi
sasa wanaweza kujenga piramidi.

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Moja ya mbinu ya tatizo hili kuweka ni
kwamba tuna kuanza saa juu ya

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piramidi.

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Huwezi printf chini ya
piramidi na kisha kujenga njia yako juu.

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Basi hebu tuangalie mfano
kutoka pset spec.

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>> Tunaona hapa kwamba wakati sisi kuingia urefu
ya 8, chini kabisa ya

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piramidi Prints hashes tisa.

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Moja ngazi ya juu na kwamba prints
nafasi moja na hashes nane.

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Moja ngazi ya juu na kwamba ni nafasi mbili na
hashes saba, njia yote mpaka sisi

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kupata juu ya piramidi, ambayo ni
ngazi nane up, ambayo Prints saba

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nafasi na hashes mbili.

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Basi kumbuka kwamba tuna
kufanya ngazi hii ya juu kwanza.

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>> Hapa sisi ni iterating kutoka
ngazi ya juu, safu ya 8, kuendelea

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mpaka mstari fika 0.

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Nafasi Hivyo ni jinsi wengi hawakuwa tunahitaji
magazeti katika mstari kwamba juu?

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Sisi kuchapishwa nafasi saba
na hashes mbili.

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Hivyo idadi ya nafasi tunataka ni
mstari waliokuwa juu ya minus 1.

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>> Kama safu ya juu ni 8, 8 minus
1 inatupa nafasi saba.

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Basi tuna kitanzi kwamba magazeti
nje kila mmoja nafasi ya wakati huo.

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Hivyo wakati nafasi ni 7, kitanzi hii
mara saba, uchapishaji

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saba nafasi ya mtu binafsi.

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>> Hivyo sasa tunahitaji magazeti hashes haya
mwishoni mwa piramidi.

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Hivyo hapa, tunahitaji mahesabu ya
idadi ya hashes.

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Tunaona kwamba sisi ni kufanya urefu
minus mstari plus 2.

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Hivyo ni jinsi gani sisi kupata kwamba?

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>> Kumbuka kwamba juu ya piramidi
ni mstari 8, na urefu ni 8.

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Na sisi bado kuchapishwa hashes mbili.

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Basi angalau sana, 8 minus 8 pamoja na
2 inatupa jibu sahihi.

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Na kisha kufikiria chini
ya piramidi, mstari 1.

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Mstari urefu minus kutupa 7, na
kisha plus 2 inatupa hashes tisa,

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ambayo ni hasa idadi
ya hashes kwamba sisi kuchapishwa.

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Hivyo hii ni formula tunataka
kutumia hesabu

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hashes katika kila mstari.

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>> Kutumia idadi hiyo, sisi kisha na mwingine
kwa kitanzi, sawa na

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kwa kitanzi kwamba sisi kutumika kwa ajili ya maeneo,
kwamba iterates idadi ya hashes mara

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uchapishaji hash moja kila wakati.

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On mstari wa juu, kwamba utakuwa
magazeti hashes mbili.

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Juu ya mstari wa chini, kwamba utakuwa
magazeti hashes tisa.

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Na kila mstari wengine magazeti kila
idadi ya hashes katika kati ya.

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>> Na kisha mwishoni sana, tunahitaji
magazeti line wetu mpya kwenda ijayo

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mstari katika piramidi.

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Hatimaye, tunahitaji magazeti line mpya
mwishoni mwa mfululizo ili uweze

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kuendelea ijayo
mstari wa piramidi.

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Na mwisho wa mpango wetu,
sisi kuwa na kurudi 0.

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>> Kama kwa pset spec, kurudi
0 si madhubuti muhimu.

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Lakini haina yanamaanisha kwamba kuu ni kosa.

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Jina langu ni Rob, na hii ilikuwa Mario.

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>> [Music kucheza]

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