leetCode笔记

LeetCode笔记：167. Two Sum II - Input array is sorted

问题：Givenanarrayofintegersthatisalreadysortedinascendingorder,findtwonumberssuchthattheyadduptoaspecifictargetnumber.ThefunctiontwoSumshouldreturnindicesofthetwonumberssuchthattheyadduptothetarget,wher
Cloudox_·2017-01-04 09:34

LeetCode笔记：6. ZigZag Conversion

问题：Thestring“PAYPALISHIRING”iswritteninazigzagpatternonagivennumberofrowslikethis:(youmaywanttodisplaythispatterninafixedfontforbetterlegibility)PAHNAPLSIIGYIRAndthenreadlinebyline:“PAHNAPLSIIGYIR”Wri
Cloudox_·2016-12-16 10:11

LeetCode笔记：190. Reverse Bits

问题：Reversebitsofagiven32bitsunsignedinteger.Forexample,giveninput43261596(representedinbinaryas00000010100101000001111010011100),return964176192(representedinbinaryas00111001011110000010100101000000).
Cloudox_·2016-12-06 09:54

LeetCode笔记：396. Rotate Function

问题：GivenanarrayofintegersAandletntobeitslength.AssumeBktobeanarrayobtainedbyrotatingthearrayAkpositionsclock-wise,wedefinea“rotationfunction”FonAasfollow:F(k)=0*Bk[0]+1*Bk[1]+…+(n-1)*Bk[n-1].Calculate
Cloudox_·2016-12-05 09:32

LeetCode笔记：400. Nth Digit

问题：Findthenthdigitoftheinfiniteintegersequence1,2,3,4,5,6,7,8,9,10,11,…Note:nispositiveandwillfitwithintherangeofa32-bitsignedinteger(nreduce+num*i){lastNum=lastNum+num;reduce=reduce+num*i;num=num*10;
Cloudox_·2016-12-01 14:19

LeetCode笔记：203. Remove Linked List Elements

问题：Removeallelementsfromalinkedlistofintegersthathavevalueval.ExampleGiven:1–>2–>6–>3–>4–>5–>6,val=6Return:1–>2–>3–>4–>5大意：移除链表中素有值为val的元素。例子：给出:1–>2–>6–>3–>4–>5–>6,val=6返回:1–>2–>3–>4–>5思路：这道题没什么特殊的，遍
Cloudox_·2016-11-30 10:44

LeetCode笔记：234. Palindrome Linked List

问题：Givenasinglylinkedlist,determineifitisapalindrome.Followup:CouldyoudoitinO(n)timeandO(1)space?大意：给出一个单链表，判断它是否是回文。进阶：你能在O（n）的时间复杂度和O（1）的空间复杂度下来做吗？思路：回文的意思就是正着读反着读都是一样的。这道题我使用简单的思路，一个个遍历链表节点来倒序组成一个新
Cloudox_·2016-11-25 09:53

LeetCode笔记：88. Merge Sorted Array

问题：Giventwosortedintegerarraysnums1andnums2,mergenums2intonums1asonesortedarray.Note:Youmayassumethatnums1hasenoughspace(sizethatisgreaterorequaltom+n)toholdadditionalelementsfromnums2.Thenumberofelem
Cloudox_·2016-11-24 14:01

LeetCode笔记：459. Repeated Substring Pattern

问题：Givenanon-emptystringcheckifitcanbeconstructedbytakingasubstringofitandappendingmultiplecopiesofthesubstringtogether.YoumayassumethegivenstringconsistsoflowercaseEnglishlettersonlyanditslengthwilln
Cloudox_·2016-11-20 14:31

LeetCode笔记：455. Assign Cookies

问题：Assumeyouareanawesomeparentandwanttogiveyourchildrensomecookies.But,youshouldgiveeachchildatmostonecookie.Eachchildihasagreedfactorgi,whichistheminimumsizeofacookiethatthechildwillbecontentwith;and
Cloudox_·2016-11-19 19:24

LeetCode笔记：38. Count and Say

问题：Thecount-and-saysequenceisthesequenceofintegersbeginningasfollows:1,11,21,1211,111221,…1isreadoffas“one1”or11.11isreadoffas“two1s”or21.21isreadoffas“one2,thenone1”or1211.Givenanintegern,generatethe
Cloudox_·2016-11-16 11:23

LeetCode笔记：111. Minimum Depth of Binary Tree

问题：Givenabinarytree,finditsminimumdepth.Theminimumdepthisthenumberofnodesalongtheshortestpathfromtherootnodedowntothenearestleafnode.大意：给出一个二叉树，找到他最小的深度。最小的深度是指从根节点到叶子节点距离最短的节点数。思路：这道题要找到最短的深度，个人认为更应该
Cloudox_·2016-11-15 09:10

LeetCode笔记：112. Path Sum

问题：Givenabinarytreeandasum,determineifthetreehasaroot-to-leafpathsuchthataddingupallthevaluesalongthepathequalsthegivensum.Forexample:Giventhebelowbinarytreeandsum=22,returntrue,asthereexistaroot-to-l
Cloudox_·2016-11-11 09:00

LeetCode笔记：299. Bulls and Cows

问题：YouareplayingthefollowingBullsandCowsgamewithyourfriend:Youwritedownanumberandaskyourfriendtoguesswhatthenumberis.Eachtimeyourfriendmakesaguess,youprovideahintthatindicateshowmanydigitsinsaidguessm
Cloudox_·2016-11-10 10:00

LeetCode笔记：374. Guess Number Higher or Lower

问题：WeareplayingtheGuessGame.Thegameisasfollows:Ipickanumberfrom1ton.YouhavetoguesswhichnumberIpicked.Everytimeyouguesswrong,I’lltellyouwhetherthenumberishigherorlower.Youcallapre-definedAPIguess(intnu
Cloudox_·2016-11-09 10:00

LeetCode笔记：438. Find All Anagrams in a String

问题：Givenastringsandanon-emptystringp,findallthestartindicesofp’sanagramsins.StringsconsistsoflowercaseEnglishlettersonlyandthelengthofbothstringssandpwillnotbelargerthan20,100.Theorderofoutputdoesnotm
Cloudox_·2016-11-08 11:00

LeetCode笔记：257. Binary Tree Paths

问题：Givenabinarytree,returnallroot-to-leafpaths.Forexample,giventhefollowingbinarytree:1/\23\5Allroot-to-leafpathsare:[“1->2->5”,“1->3”]大意：给出一个二叉树，返回所有从根节点到叶子节点的路径。比如给出下面这个二叉树：1/\23\5所有从根节点到叶子节点的路径为：[“
Cloudox_·2016-11-07 11:00

LeetCode笔记：9. Palindrome Number

问题：Determinewhetheranintegerisapalindrome.Dothiswithoutextraspace.大意：判断一个整数是否是回文。不使用额外的空间来完成。思路：这道题目很简单，只有一句话，不要要求不使用额外空间，一般来说不使用额外空间的意思是不使用复杂度为O（n）的额外空间，新建一些字符串、整型值之类的还是可以的。回文的意思是从左到右读和从右到左读数字是一样的，比如
Cloudox_·2016-11-04 09:00

LeetCode笔记：437. Path Sum III

问题：Youaregivenabinarytreeinwhicheachnodecontainsanintegervalue.Findthenumberofpathsthatsumtoagivenvalue.Thepathdoesnotneedtostartorendattherootoraleaf,butitmustgodownwards(travelingonlyfromparentnodes
Cloudox_·2016-11-03 10:17

LeetCode笔记：437. Path Sum III

问题：Youaregivenabinarytreeinwhicheachnodecontainsanintegervalue.Findthenumberofpathsthatsumtoagivenvalue.Thepathdoesnotneedtostartorendattherootoraleaf,butitmustgodownwards(travelingonlyfromparentnodes
Cloudox_·2016-11-03 10:00

LeetCode笔记：441. Arranging Coins

问题：Youhaveatotalofncoinsthatyouwanttoforminastaircaseshape,whereeveryk-throwmusthaveexactlykcoins.Givenn,findthetotalnumberoffullstaircaserowsthatcanbeformed.nisanon-negativeintegerandfitswithintheran
Cloudox_·2016-11-02 10:14

LeetCode笔记：441. Arranging Coins

问题：Youhaveatotalofncoinsthatyouwanttoforminastaircaseshape,whereeveryk-throwmusthaveexactlykcoins.Givenn,findthetotalnumberoffullstaircaserowsthatcanbeformed.nisanon-negativeintegerandfitswithintheran
Cloudox_·2016-11-02 10:00

LeetCode笔记：412. Fizz Buzz

问题：Writeaprogramthatoutputsthestringrepresentationofnumbersfrom1ton.Butformultiplesofthreeitshouldoutput“Fizz”insteadofthenumberandforthemultiplesoffiveoutput“Buzz”.Fornumberswhicharemultiplesofbothth
Cloudox_·2016-11-02 08:20

LeetCode笔记：412. Fizz Buzz

问题：Writeaprogramthatoutputsthestringrepresentationofnumbersfrom1ton.Butformultiplesofthreeitshouldoutput“Fizz”insteadofthenumberandforthemultiplesoffiveoutput“Buzz”.Fornumberswhicharemultiplesofbothth
Cloudox_·2016-11-02 08:00

LeetCode笔记：119. Pascal's Triangle II

问题：Givenanindexk,returnthekthrowofthePascal’striangle.Forexample,givenk=3,Return[1,3,3,1].Note:CouldyouoptimizeyouralgorithmtouseonlyO(k)extraspace?大意：给出一个序号k，返回杨辉三角形的第k行。比如给出k=3，返回[1,3,3,1]。注意：你能不能让你
Cloudox_·2016-11-01 09:00

LeetCode笔记：172. Factorial Trailing Zeroes

问题：Givenanintegern,returnthenumberoftrailingzeroesinn!.Note:Yoursolutionshouldbeinlogarithmictimecomplexity.大意：给出一个整数n，返回n!后面0的个数。注意：你的算法时间复杂度要是logn以内。思路：这道题的要求是计算n的阶乘后面0的个数，而且要求算法时间复杂度为logn，那么就绝对不是要人
Cloudox_·2016-10-31 09:56

LeetCode笔记：172. Factorial Trailing Zeroes

问题：Givenanintegern,returnthenumberoftrailingzeroesinn!.Note:Yoursolutionshouldbeinlogarithmictimecomplexity.大意：给出一个整数n，返回n!后面0的个数。注意：你的算法时间复杂度要是logn以内。思路：这道题的要求是计算n的阶乘后面0的个数，而且要求算法时间复杂度为logn，那么就绝对不是要人
Cloudox_·2016-10-31 09:00

LeetCode笔记：232. Implement Queue using Stacks

问题：Implementthefollowingoperationsofaqueueusingstacks.push(x)–Pushelementxtothebackofqueue.pop()–Removestheelementfrominfrontofqueue.peek()–Getthefrontelement.empty()–Returnwhetherthequeueisempty.Note
Cloudox_·2016-10-28 15:07

LeetCode笔记：232. Implement Queue using Stacks

问题：Implementthefollowingoperationsofaqueueusingstacks.push(x)–Pushelementxtothebackofqueue.pop()–Removestheelementfrominfrontofqueue.peek()–Getthefrontelement.empty()–Returnwhetherthequeueisempty.Note
Cloudox_·2016-10-28 15:07

LeetCode笔记：232. Implement Queue using Stacks

问题：Implementthefollowingoperationsofaqueueusingstacks.push(x)–Pushelementxtothebackofqueue.pop()–Removestheelementfrominfrontofqueue.peek()–Getthefrontelement.empty()–Returnwhetherthequeueisempty.Note
Cloudox_·2016-10-28 15:00

LeetCode笔记：26. Remove Duplicates from Sorted Array

问题：Givenasortedarray,removetheduplicatesinplacesuchthateachelementappearonlyonceandreturnthenewlength.Donotallocateextraspaceforanotherarray,youmustdothisinplacewithconstantmemory.Forexample,Giveninpu
Cloudox_·2016-10-27 09:24

LeetCode笔记：26. Remove Duplicates from Sorted Array

问题：Givenasortedarray,removetheduplicatesinplacesuchthateachelementappearonlyonceandreturnthenewlength.Donotallocateextraspaceforanotherarray,youmustdothisinplacewithconstantmemory.Forexample,Giveninpu
Cloudox_·2016-10-27 09:24

LeetCode笔记：26. Remove Duplicates from Sorted Array

问题：Givenasortedarray,removetheduplicatesinplacesuchthateachelementappearonlyonceandreturnthenewlength.Donotallocateextraspaceforanotherarray,youmustdothisinplacewithconstantmemory.Forexample,Giveninpu
Cloudox_·2016-10-27 09:00

LeetCode笔记：110. Balanced Binary Tree

问题：Givenabinarytree,determineifitisheight-balanced.Forthisproblem,aheight-balancedbinarytreeisdefinedasabinarytreeinwhichthedepthofthetwosubtreesofeverynodeneverdifferbymorethan1.大意：给出一个二叉树，判断它高度是不是平衡
Cloudox_·2016-10-26 14:00

LeetCode笔记：102. Binary Tree Level Order Traversal

问题：Givenabinarytree,returnthelevelordertraversalofitsnodes’values.(ie,fromlefttoright,levelbylevel).Forexample:Givenbinarytree[3,9,20,null,null,15,7],3/\920/\157returnitslevelordertraversalas:[[3],[9,
Cloudox_·2016-10-25 09:00

LeetCode笔记：118. Pascal's Triangle

问题：GivennumRows,generatethefirstnumRowsofPascal’striangle.Forexample,givennumRows=5,Return[[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]大意：给出一个行数，生出对应行数的杨辉三角形。比如，给出行数=5。返回[[1],[1,1],[1,2,1],[1,3,3,1],[1,4,
Cloudox_·2016-10-24 09:00

LeetCode笔记：101. Symmetric Tree

问题：Givenabinarytree,checkwhetheritisamirrorofitself(ie,symmetricarounditscenter).Forexample,thisbinarytree[1,2,2,3,4,4,3]issymmetric:1/\２2/\/\3443Butthefollowing[1,2,2,null,3,null,3]isnot:1/\22\\33Not
Cloudox_·2016-10-20 09:00

LeetCode笔记：27. Remove Element

问题：Givenanarrayandavalue,removeallinstancesofthatvalueinplaceandreturnthenewlength.Donotallocateextraspaceforanotherarray,youmustdothisinplacewithconstantmemory.Theorderofelementscanbechanged.Itdoesn’
Cloudox_·2016-10-19 09:00

LeetCode笔记：66. Plus One

问题：Givenanon-negativenumberrepresentedasanarrayofdigits,plusonetothenumber.Thedigitsarestoredsuchthatthemostsignificantdigitisattheheadofthelist.大意：给出一个非负数的代表数字的数组，给这个“数字”加一。这个数字的存储形式为最高位的数再数组的最前端。思路：
Cloudox_·2016-10-18 09:00

LeetCode笔记：141. Linked List Cycle

问题：Givenalinkedlist,determineifithasacycleinit.Followup:Canyousolveitwithoutusingextraspace?大意：给出一个链表，判断它有没有回环。进阶：你能不能不用额外的空间来解决？思路：这道题我利用Java中Set集合的特性，即集合中不允许出现相同的对象。我们遍历链表，边遍历边把每个节点放入一个Set集合中，并且每次都判
Cloudox_·2016-10-12 10:00

LeetCode笔记：107. Binary Tree Level Order Traversal II

问题：Givenabinarytree,returnthebottom-uplevelordertraversalofitsnodes’values.(ie,fromlefttoright,levelbylevelfromleaftoroot).Forexample:Givenbinarytree[3,9,20,null,null,15,7],3/\920/\157returnitsbottom-
Cloudox_·2016-10-11 10:00

LeetCode笔记：415. Add Strings

问题：Giventwonon-negativenumbersnum1andnum2representedasstring,returnthesumofnum1andnum2.Note:1、Thelengthofbothnum1andnum2is=0||j>=0){ intn1=i>=0?num1.charAt(i)-'0':0; intn2=j>=0?num2.charAt(j)-'0':0; i
Cloudox_·2016-10-10 09:00

LeetCode笔记：235. Lowest Common Ancestor of a Binary Search Tree

问题：Givenabinarysearchtree(BST),findthelowestcommonancestor(LCA)oftwogivennodesintheBST.AccordingtothedefinitionofLCAonWikipedia:“ThelowestcommonancestorisdefinedbetweentwonodesvandwasthelowestnodeinTt
Cloudox_·2016-09-27 10:00

LeetCode笔记：121. Best Time to Buy and Sell Stock

问题：Sayyouhaveanarrayforwhichtheithelementisthepriceofagivenstockondayi.Ifyouwereonlypermittedtocompleteatmostonetransaction(ie,buyoneandselloneshareofthestock),designanalgorithmtofindthemaximumprofit.
Cloudox_·2016-09-26 10:00

LeetCode笔记：404. Sum of Left Leaves

问题：Findthesumofallleftleavesinagivenbinarytree.Example:3 /\ 920 /\ 157 Therearetwoleftleavesinthebinarytree,withvalues9and15respectively.Return24.大意：计算一个二叉树中所有左叶子节点的和例子:3 /\ 920 /\ 157 在这个二叉树中有两个左叶子节点
Cloudox_·2016-09-26 09:00

LeetCode笔记：70. Climbing Stairs

问题：Youareclimbingastaircase.Ittakesnstepstoreachtothetop.Eachtimeyoucaneitherclimb1or2steps.Inhowmanydistinctwayscanyouclimbtothetop?大意：你在爬一个楼梯。需要n节楼梯到达顶部。每次你可以爬一节或者两节楼梯。你总共有多少种爬到顶部的方法？思路：总觉得这个题目小时候做过
Cloudox_·2016-09-23 09:00

LeetCode笔记：263. Ugly Number

问题：Writeaprogramtocheckwhetheragivennumberisanuglynumber.Uglynumbersarepositivenumberswhoseprimefactorsonlyinclude2,3,5.Forexample,6,8areuglywhile14isnotuglysinceitincludesanotherprimefactor7.Notethat
Cloudox_·2016-09-22 09:00

LeetCode笔记：350. Intersection of Two Arrays II

问题：Giventwoarrays,writeafunctiontocomputetheirintersection.Example:Givennums1=[1,2,2,1],nums2=[2,2],return[2,2].Note:Eachelementintheresultshouldappearasmanytimesasitshowsinbotharrays.Theresultcanbein
Cloudox_·2016-09-14 14:00

LeetCode笔记：387. First Unique Character in a String

问题：Givenastring,findthefirstnon-repeatingcharacterinitandreturnit’sindex.Ifitdoesn’texist,return-1.Examples:s=“leetcode”return0.s=“loveleetcode”,return2.Note:Youmayassumethestringcontainonlylowercasel
Cloudox_·2016-09-13 09:00

LeetCode笔记：136. Single Number

问题：Givenanarrayofintegers,everyelementappearstwiceexceptforone.Findthatsingleone.Note:Youralgorithmshouldhavealinearruntimecomplexity.Couldyouimplementitwithoutusingextramemory?大意：给出一个整数数组，其中每个元素都出现了两
Cloudox_·2016-09-07 14:00
上一页 8 9 10 11 12 13 14 15 下一页
按字母分类： ABCDEFGHIJKLMNOPQRSTUVWXYZ其他