Problem link: http://oj.leetcode.com/problems/single-number-ii/ The problem seems like the Single Number. Suppose we have following (3m+1) numbers in the array A: x0, x1, x1, x1, ..., xm, xm, xm We are asked to find out the value of x0. However we ca…

Prolbem link: http://oj.leetcode.com/problems/single-number/ This prolbem can be solved by using XOR(exclusive OR) operation. Let x, y, and z be any numbers, and XOR has following properties: x XOR 0 is itself, i.e. x XOR 0 = 0; x XOR x is 0, i.e. x…

问题描述:给出一个整数数组,除了一个元素外,其他每个元素都出现了2次,找出只出现1次的元素. int singleNumber(vector<int>& nums); 分析:比较自然的想法是用一个容器来进行插入.查找.删除操作.遍历nums,先查找容器中是否包含该元素,是则插入,否则删除.最后容器中只剩下只出现1次的元素. 解法: int singleNumber(vector<int>& nums) { int i = 0; unordered_set<in…

Problem Link: http://oj.leetcode.com/problems/interleaving-string/ Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example, Given: s1 = "aabcc", s2 = "dbbca", When s3 = "aadbbcbcac", return t…

Problem link: http://oj.leetcode.com/problems/reverse-words-in-a-string/ Given an input string, reverse the string word by word. For example, Given s = "the sky is blue", return "blue is sky the". LeetCode OJ supports Python now! The s…

今天做了三道LeetCode上的简单题目,每道题都是用c++和Python两种语言写的.由于c++版的代码网上比較多.所以就仅仅分享一下Python的代码吧,刚学完Python的基本的语法,做做LeetCode的题目还是不错的,对以后找工作面试也有帮助! 刚開始就从AC率最高的入手吧! 1.Given an array of integers, every element appears twice except for one. Find that single one. Note: Your…

Problem Link: https://oj.leetcode.com/problems/maximum-depth-of-binary-tree/ Simply BFS from root and count the number of levels. The code is as follows. # Definition for a binary tree node # class TreeNode: # def __init__(self, x): # self.val = x #…

Problem Link: http://oj.leetcode.com/problems/triangle/ Let R[][] be a 2D array where R[i][j] (j <= i) is the minimum sum of the path from triangle[0][0] to tirangle[i][j]. We initialize R[0][0] = triangle[0][0], and update R[][] from i = 1 to n-1: R…

Problem Link: http://oj.leetcode.com/problems/best-time-to-buy-and-sell-stock-iii/ Linear Time Solution We try to solve this problem in O(n) time in the help of the algorithm in Best Time to Buy and Sell Stock, which can return the max profit by give…

Problem Link: http://oj.leetcode.com/problems/word-ladder/ Two typical techniques are inspected in this problem: Hash Table. One hash set is the words dictionary where we can check if a word is in the dictionary in O(1) time. The other hash set is us…