一入深似海系列課程-二期四節(jié)集合框架算法運(yùn)用

「一入Java深似講師信?勸退師，ApacheCloud??「一入Java深似講師信?勸退師，ApacheCloud????主要議?實(shí)?二分搜索算?Java二分搜索算法主要議?實(shí)?二分搜索算?Java二分搜索算法實(shí)?課程總?基本介Analgorithmthatputselementsofalistinacertainorder.Themostfrequentlyusedordersarenumericalorderandlexicographicalorder.基本介Analgorithmthatputselementsofalistinacertainorder.Themostfrequentlyusedordersarenumericalorderandlexicographicalorder.Efficientsortingisimportantforoptimizingtheefficiencyofotheralgorithms(suchassearchandmergealgorithms)whichrequireinputdatatobeinsortedlists.Sortingisalsooftenusefulforcanonicalizingdataandforproducinghuman-readableoutput.Moreformally,theoutputofanysortingalgorithmmustsatisfytwo?Theoutputisinnondecreasingorder(eachelementisnosmallerthanthepreviouselementaccordingtothedesiredtotalorder);?Theoutputisapermutation(areordering,yetretainingalloftheoriginalelements)ofthe?分????穩(wěn)定性：當(dāng)相同的健存在時(shí)，經(jīng)過排序后，其值也保持相對(duì)的順序（不發(fā)生變化??分????穩(wěn)定性：當(dāng)相同的健存在時(shí)，經(jīng)過排序后，其值也保持相對(duì)的順序（不發(fā)生變化??分??分??計(jì)算復(fù)雜度計(jì)算復(fù)雜度?Theamountofresourcesrequiredforrunningit.Thecomputationalcomplexityofaproblemistheminimumofthecomplexitiesofallpossiblealgorithmsforthisproblem(includingtheunknownalgorithms).Astheamountofneededresourcesvarieswiththeinput,thecomplexityisgenerallyexpressedasafunctionn→f(n),wherenisthesizeoftheinput,andf(n)iseithertheworst-casecomplexity,thatisthemaximumoftheamountofresourcesthatareneededforallinputsofsizen,ortheaverage-casecomplexity,thatisaverageoftheamountofresourcesoverallinputofsizen.計(jì)算復(fù)雜度計(jì)算復(fù)雜度?Whenthenatureoftheresourcesisnotexplicitlygiven,thisisusuallythetimeneededforrunningthealgorithm,andonetalksoftimecomplexity.However,thisdependsonthecomputerthatisused,andthetimeisgenerallyexpressedasthenumberofneededelementaryoperations,whicharesupposedtotakeaconstanttimeonagivencomputer,andtochangebyaconstantfactorwhenonechangesofcomputer.Otherwise,theresourcethatisconsideredisoftenthesizeofthememorythatisneeded,andonetalksofspacecomplexity.時(shí)間復(fù)雜度（時(shí)間復(fù)雜度（Time?Theamountoftimeittakestorunanalgorithm.Timecomplexityiscommonlyestimatedbycountingthenumberofelementaryoperationsperformedbythealgorithm,supposingthateachelementaryoperationtakesafixedamountoftimetoperform.Thus,theamountoftimetakenandthenumberofelementaryoperationsperformedbythealgorithmaretakentodifferbyatmostaconstantfactor.時(shí)間復(fù)雜度（時(shí)間復(fù)雜度（Time?Sinceanalgorithm'srunningtimemayvaryamongdifferentinputsofthesamesize,onecommonlyconsiderstheworst-casetimecomplexity,whichisthemaximumamountoftimerequiredforinputsofagivensize.Lesscommon,andusuallyspecifiedexplicitly,istheaverage-casecomplexity,whichistheaverageofthetimetakenoninputsofagivensize(thismakessensebecausethereareonlyafinitenumberofpossibleinputsofagivensize).Inbothcases,thetimecomplexityisgenerallyexpressedasafunctionofthesizeoftheinput.Sincethisfunctionisgenerallydifficulttocomputeexactly,andtherunningtimeforsmallinputsisusuallynotconsequential,onecommonlyfocusesonthebehaviorofthecomplexitywhentheinputsizeincreases—thatis,theasymptoticbehaviorofthe時(shí)間復(fù)雜度（Time?表達(dá)式：BigO?常量時(shí)間：T(n)O(1)（數(shù)組隨機(jī)訪問?線性時(shí)間：T(n)=O(n)（在未排序數(shù)組中找尋最值?時(shí)間復(fù)雜度（Time?表達(dá)式：BigO?常量時(shí)間：T(n)O(1)（數(shù)組隨機(jī)訪問?線性時(shí)間：T(n)=O(n)（在未排序數(shù)組中找尋最值?對(duì)數(shù)時(shí)間：T(n)=O(logn)（二進(jìn)制搜索?指數(shù)時(shí)間：T(n)=O(n^c)（冒泡排序、插入排序?BigO??無限漸進(jìn)?無限小漸進(jìn)BigO??無限漸進(jìn)?無限小漸進(jìn)?穩(wěn)定性穩(wěn)定性?Stablesortalgorithmssortrepeatedelementsinthesameorderthattheyappearintheinput.Whensortingsomekindsofdata,onlypartofthedataisexaminedwhendeterminingthesortorder.Forexample,inthecardsortingexampletotheright,thecardsarebeingsortedbytheirrank,andtheirsuitisbeingignored.Thisallowsthepossibilityofmultipledifferentcorrectlysortedversionsoftheoriginallist.Stablesortingalgorithmschooseoneofthese,accordingtothefollowingrule:iftwoitemscompareasequal,likethetwo5cards,thentheirrelativeorderwillbepreserved,sothatifonecamebeforetheotherintheinput,itwillalsocomebeforetheotherintheoutput.穩(wěn)定性??穩(wěn)定性??穩(wěn)定性??穩(wěn)定性??比較排?Acomparisonsortisatypeofsortingalgorithmthatonlyreadsthelistelementsthroughasingleabstractcomparison比較排?Acomparisonsortisatypeofsortingalgorithmthatonlyreadsthelistelementsthroughasingleabstractcomparisonoperation(oftena"lessthanorequalto"operatororathree-waycomparison)thatdetermineswhichoftwoelementsshouldoccurfirstinthefinalsortedlist.Theonlyrequirementisthattheoperatorobeytwoofthepropertiesofatotalifa≤bandb≤cthena≤cforallaandb,eithera≤borb≤a(totalnessor比較排?冒泡排序（BubbleSort）：最佳O(n)、平均O(n^2)、最壞?插入排序（InsertionSort）：最佳O(n)、平均O(n^2)、最壞?快速排序（QuickSort）：最佳O(nlogn)、平均比較排?冒泡排序（BubbleSort）：最佳O(n)、平均O(n^2)、最壞?插入排序（InsertionSort）：最佳O(n)、平均O(n^2)、最壞?快速排序（QuickSort）：最佳O(nlogn)、平均O(nlogn)、最壞?合并排序（MergeSort）：最佳O(nlogn)、平均O(nlogn)、最壞?Tim排序（TimSort）：最佳O(n)、平均O(nlogn)、最壞?冒泡排序（Bubble?時(shí)間復(fù)雜度：最佳O(n)、平均O(n^2)冒泡排序（Bubble?時(shí)間復(fù)雜度：最佳O(n)、平均O(n^2)、最壞??插入排序（Insertion?時(shí)間復(fù)雜度：最佳O(n)、平均O(n^2)插入排序（Insertion?時(shí)間復(fù)雜度：最佳O(n)、平均O(n^2)、最壞??快速排序（Quick?時(shí)間復(fù)雜度：最佳O(nlogn)、平均O(nlogn)、最壞??獲取pivot（軸?分區(qū)快速排序（Quick?時(shí)間復(fù)雜度：最佳O(nlogn)、平均O(nlogn)、最壞??獲取pivot（軸?分區(qū)?遞歸?快速排序（Quick快速排序（Quick??合并排序（Merge?時(shí)間復(fù)雜度：最佳O(nlogn)、平均O(nlogn)、最壞??分塊合并排序（Merge?時(shí)間復(fù)雜度：最佳O(nlogn)、平均O(nlogn)、最壞??分塊?遞歸合并?合并排序（Merge合并排序（Merge??Tim排序?時(shí)間復(fù)雜度：最佳O(n)、平均O(nlogn)、最壞Tim排序?時(shí)間復(fù)雜度：最佳O(n)、平均O(nlogn)、最壞??實(shí)實(shí)集合框?qū)崈?nèi)建實(shí)?冒泡排序?插入排序（7時(shí)?快速排序?合并排序Sort）：java.util.Arrays#mergeSort集合框?qū)崈?nèi)建實(shí)?冒泡排序?插入排序（7時(shí)?快速排序?合并排序Sort）：java.util.Arrays#mergeSort之后需要激活?Tim排序?二分搜索（Binary二分搜索（Binary?Alsoknownashalf-intervalsearch,logarithmicsearch,orbinarychop,isasearchalgorithmthatfindsthepositionofatargetvaluewithinasortedarray.Binarysearchcomparesthetargetvaluetothemiddleelementofthearray.Iftheyarenotequal,thehalfinwhichthetargetcannotlieiseliminatedandthesearchcontinuesontheremaininghalf,againtakingthemiddleelementtocomparetothetarget