博客搬至blog.csgrandeur.com,cnblogs不再更新. 新的题解会更新在新博客:http://blog.csgrandeur.com/2014/01/15/LeetCode-OJ-Solution/ ———————————————————————————————————————— ———————————————————————————————————————— LeetCode OJ 题解 LeetCode OJ is a platform for preparing tech…

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…

一直没有系统地学习过算法,不过算法确实是需要系统学习的.大二上学期,在导师的建议下开始学习数据结构,零零散散的一学期,有了链表.栈.队列.树.图等的概念.又看了下那几个经典的算法——贪心算法.分治算法.动态规划以及回溯算法.不过,都是知其一不知其二的一知半解.到最后,发现学到了一堆的一知半解,在学校课程开这门课时,却又是不得不再学一遍.学一样东西,又不全心全意地主动去把它学好,到最后只是花费了时间,却没真真学到东西.所以,不求学识有多广,但求所学的都精. 一个偶然的机会,让我在网上找到了一本社区…

Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another comput…

常泡LC的朋友知道LC是不提供代码打包下载的,不像一般的OJ,可是我不备份代码就感觉不舒服- 其实我想说的是- 我自己写了抓取个人提交代码的小工具,放在GitCafe上了- 不知道大家有没有兴趣 https://gitcafe.com/aaronzhou/ ... ssion 拿Java写的,也打了一个包,本地有JRE环境就能运行,欢迎拍砖 抓取 LeetCode OJ 个人提交的代码 Gradle 构建项目 HttpClient.jsoup 抓取.解析网页 使用说明 进入release文件夹…

题目: Given a 2D binary matrix filled with 0's and 1's, find the largest square containing all 1's and return its area. For example, given the following matrix: 1 0 1 0 0 1 0 1 1 1 1 1 0 0 1 0 Return 4. 题目链接:https://leetcode.com/problems/maximal-square…

Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 给定一个整数,将他转换到罗马字符.同样这里的罗马字符不会超过1000(M),PS:关于罗马字符的介绍看我的这篇文章 :LeetCode OJ:Roman to Integer(转换罗马字符到整数) 这里的大体思路是这样的,例如对于罗马字符952来说,起答题的可以分成三个组成部分, 就…

Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another comput…

索引:[LeetCode] Leetcode 题解索引 (C++/Java/Python/Sql) Github: https://github.com/illuz/leetcode 038. Count and Say (Easy) 链接: 题目:https://leetcode.com/problems/Count-and-Say/ 代码(github):https://github.com/illuz/leetcode 题意: 数数.第一个是 1,第二个是数前一个数:1 个 1,就是 11…

Total Accepted: 32628 Total Submissions: 129569 Difficulty: Medium Given a complete binary tree, count the number of nodes. Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is comple…

Count the number of prime numbers less than a non-negative number, n. 计算小于n的质数的个数,当然就要用到大名鼎鼎的筛法了,代码如下,写的有点乱不好意思. class Solution { public: int countPrimes(int n) { vector<, ); vector<int> ret; ; i <= n; ++i) vtor[i] = i; ; i < n; ++i){//边界条件…

Given a complete binary tree, count the number of nodes. Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as pos…

The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ... 1 is read off as "one 1" or 11.11 is read off as "two 1s" or 21.21 is read off as "one 2, then one 1" or 1211. Given an…

Description: Count the number of prime numbers less than a non-negative number, n. 分析: 思路首先:一个数不是合数就是素数,合数更好推断呢! 合数:不论什么一个合数都能够表现为适当个素数的乘积的形式, 所以我们仅仅用小于sqrt(number)的素数去除要推断的数就可以, 由于合数在sqrt(number)以内一定有素数的质因子 比方要推断100以内的素数,仅仅需推断合数就可以.仅仅用10以内的2,3.5.7就够…

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/distinct-subsequences/ A classic problem using Dynamic Programming technique. Let m and n be the length of the strings T and S. Let R[i][j] be the count of distinct subsequence of T[0..i] in S[0..j]. Obvi…

Problem Link: http://oj.leetcode.com/problems/longest-consecutive-sequence/ This problem is a classical problem where we can reduce the running time by the help of hash table. By given a list of numbers, we can find the longest consecutive sequence b…

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…

================================== LeetCode的一些算法题,都是自己做的,欢迎提出改进~~ LeetCode:http://oj.leetcode.com ================================== <Reverse Words in a String>-20140328 Given an input string, reverse the string word by word. For example, Given s =…

Valid Palindrome吐槽一下Leetcode上各种不定义标准的输入输出(只是面试时起码能够问一下输入输出格式...),此篇文章不是详细的题解,是自己刷LeetCode的一个笔记吧,尽管没有代码,可是略微难一点的都会标出主要思路,便于以后复习 PS:题目中有"水题"两字的都是一遍AC,没有标注的都说明了问题,顺序依照Leetcode上时间倒序排列,少量题目因为和之前的题目有相关性,因此将其放在一起,比方12题和13题,因此中间可能会"缺少"几道题目,缺少的…

http://oj.leetcode.com/problems/word-ladder-ii/ class Solution { public: vector<vector<string>> findLadders(string start, string end, unordered_set<string> &dict) { //map <string,string> parentRecord; multimap<string ,string…

http://oj.leetcode.com/problems/word-ladder/ 图的最短路径问题,可以用最短路径算法,也可以深搜,也可以广搜. 深搜版本: 第一次写的时候,把sum和visited都自然的设置成了传引用,导致递归调用下去之后,再返回来,反而各种参数的值退不回来了.然后把sum和visited改成了传值,这样反而适应了本程序意图.可见,也不是什么时候都需要传引用的.具体在写程序的时候,需要传值还是传引用,要具体分析.传引用和传值的情况分别如下: void DFS(stri…

You are given an integer array nums and you have to return a new counts array. The countsarray has the property where counts[i] is the number of smaller elements to the right of nums[i]. Example: Input: [5,2,6,1] Output: [2,1,1,0] Explanation: To the…

Problem Link: https://oj.leetcode.com/problems/validate-binary-search-tree/ We inorder-traverse the tree, and for each node we check if current_node.val > prev_node.val. The code is as follows. # Definition for a binary tree node # class TreeNode: #…

Problem Link: https://oj.leetcode.com/problems/recover-binary-search-tree/ We know that the inorder traversal of a binary search tree should be a sorted array. Therefore, we can compare each node with its previous node in the inorder to find the two…

Problem Link: https://oj.leetcode.com/problems/same-tree/ The following recursive version is accepted but the iterative one is not accepted... # Definition for a binary tree node # class TreeNode: # def __init__(self, x): # self.val = x # self.left =…

Problem Link: https://oj.leetcode.com/problems/symmetric-tree/ To solve the problem, we can traverse the tree level by level. For each level, we construct an array of values of the length 2^depth, and check if this array is symmetric. The tree is sym…

Problem Link: https://oj.leetcode.com/problems/binary-tree-level-order-traversal/ Traverse the tree level by level using BFS method. # Definition for a binary tree node # class TreeNode: # def __init__(self, x): # self.val = x # self.left = None # se…

Problem Link: https://oj.leetcode.com/problems/binary-tree-zigzag-level-order-traversal/ Just BFS from the root and for each level insert a list of values into the result. # Definition for a binary tree node # class TreeNode: # def __init__(self, x):…