摘要：Valid NumberValidate if a given string is numeric.Some examples:"0"=>true" 0.1 "=>true"abc"=>false"1 a"=>false"2e10"=>trueNote:It is intended for the ... 阅读全文

摘要：Sudoku SolverWrite a program to solve a Sudoku puzzle by filling the empty cells.Empty cells are indicated by the character'.'.You may assume that the... 阅读全文

摘要：Divide Two IntegersDivide two integers without using multiplication, division and mod operator.不用* 、/、%来做除法。只能加减了啊亲！算法思路：一个一个加上去必超时，例如dividend = Integ... 阅读全文

摘要：Evaluate Reverse Polish NotationEvaluate the value of an arithmetic expression inReverse Polish Notation.Valid operators are+,-,*,/. Each operand may ... 阅读全文

摘要：Add BinaryGiven two binary strings, return their sum (also a binary string).For example,a ="11"b ="1"Return"100".算法思路：模拟二进制加法，跟十进制木有区别，将a，b转置(不转置的话，倒着... 阅读全文

摘要：ZigZag ConversionThe string"PAYPALISHIRING"is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern i... 阅读全文

摘要：Permutation SequenceThe set[1,2,3,…,n]contains a total ofn! unique permutations.By listing and labeling all of the permutations in order,We get the fo... 阅读全文

摘要：Next PermutationImplement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.If such arrangemen... 阅读全文

摘要：Permutations IIGiven a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2]have the follow... 阅读全文

摘要：Add Two NumbersYou are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes co... 阅读全文

摘要：PermutationsGiven a collection of numbers, return all possible permutations.For example,[1,2,3]have the following permutations:[1,2,3],[1,3,2],[2,1,3]... 阅读全文

摘要：CombinationsGiven two integersnandk, return all possible combinations ofknumbers out of 1 ...n.For example,Ifn= 4 andk= 2, a solution is:[ [2,4], [3... 阅读全文

摘要：Palindrome NumberDetermine whether an integer is a palindrome. Do this without extra space.click to show spoilers.Some hints:Could negative integers b... 阅读全文

摘要：Reverse IntegerReverse digits of an integer.Example1:x = 123, return 321Example2:x = -123, return -321click to show spoilers.Have you thought about th... 阅读全文

摘要：Plus OneGiven a non-negative number represented as an array of digits, plus one to the number.The digits are stored such that the most significant dig... 阅读全文

摘要：Set Matrix ZeroesGiven amxnmatrix, if an element is 0, set its entire row and column to 0. Do it in place.Follow up:Did you use extra space?A straight... 阅读全文

摘要：本文载自【k sum problem】以及【NSum】有位同僚，对该问题做出了代码的小结，想看吗？戳我戳我。问题陈述：在一个数组，从中找出k个数（每个数不能重复取。数组中同一个值有多个，可以取多个），使得和为零。找出所有这样的组合，要求没有重复项（只要值不同即可，不要求在原数组中的index不同）解... 阅读全文

摘要：4SumGiven an arraySofnintegers, are there elementsa,b,c, anddinSsuch thata+b+c+d= target? Find all unique quadruplets in the array which gives the sum... 阅读全文

摘要：3Sum ClosestGiven an arraySofnintegers, find three integers inSsuch that the sum is closest to a given number, target. Return the sum of the three int... 阅读全文

摘要：3SumGiven an arraySofnintegers, are there elementsa,b,cinSsuch thata+b+c= 0? Find all unique triplets in the array which gives the sum of zero.Note:El... 阅读全文