Big O ntsuas dab tsi?
Big O ntsuas dab tsi?

Video: Big O ntsuas dab tsi?

Video: Big O ntsuas dab tsi?
Video: Asymptotic Bounding 101: Big O, Big Omega и Theta (глубокое понимание асимптотического анализа) 2024, Tej zaum
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loj - O sau tseg. (txhais) Txhais: Kev xav theoretical ntsuas ntawm kev ua tiav ntawm cov txheej txheem, feem ntau yog lub sijhawm lossis nco xav tau, muab qhov teeb meem loj n, uas yog feem ntau tus naj npawb ntawm cov khoom. Informally, hais qee qhov sib npaug f(n) = O (g(n)) txhais tau tias nws yog tsawg dua qee qhov ntau yam ntawm g(n).

Tsis tas li ntawd, Big O txhais li cas?

Loj O Cov ntawv sau yog siv hauv Computer Science los piav txog qhov ua tau zoo lossis qhov nyuaj ntawm cov algorithm. Loj O tshwj xeeb piav qhia qhov xwm txheej phem tshaj plaws, thiab tuaj yeem siv los piav qhia lub sijhawm ua tiav lossis qhov chaw siv (piv txwv li hauv lub cim xeeb lossis ntawm disk) los ntawm cov txheej txheem.

Qhov thib ob, Big O puas yog qhov phem tshaj? Yog li, Hauv kev tshawb nrhiav binary, qhov zoo tshaj plaws cas yog O (1), nruab nrab thiab qhov phem tshaj plaws yog O (logn) ua. Hauv ntej, tsis muaj kev sib raug zoo ntawm hom big ua O yog siv rau rooj plaub , Theta rau nruab nrab cas ”. Txhua hom kev sau ntawv tuaj yeem siv tau (thiab qee zaum) siv thaum tham txog qhov zoo tshaj plaws, nruab nrab, lossis qhov phem tshaj plaws ntawm ib qho algorithm.

Ib sab saum toj no, Dab tsi yog Big O muaj nuj nqi?

Loj O cov cim yog cov lej zauv uas piav qhia txog kev txwv tus cwj pwm ntawm a muaj nuj nqi thaum qhov kev sib cav nyhav mus rau ib qho nqi lossis infinity. Kev piav qhia ntawm a muaj nuj nqi nyob rau hauv cov nqe lus ntawm big ua O cov cim feem ntau tsuas yog muab cov kab ke sab saud ntawm qhov kev loj hlob ntawm muaj nuj nqi.

Koj yuav piav qhia txog Big O qhov cim tseg li cas?

Cov Big O notation txhais ib sab qaum ntawm ib qho algorithm, nws bounds ib txoj haujlwm tsuas yog los ntawm saum toj no. Piv txwv li, xav txog rooj plaub ntawm Insertion Sort. Nws yuav siv sij hawm linear nyob rau hauv cov ntaub ntawv zoo tshaj plaws thiab lub sij hawm quadratic nyob rau hauv cov ntaub ntawv phem tshaj. Peb tuaj yeem hais tau zoo tias lub sijhawm nyuaj ntawm Kev Ntxig Ntxig yog O (n^2).

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