Basic Calculator II 题目 思路 和这个一样:Basic Calculator I 代码 class ExpressionTransformation { public: string trans_to_postfix_expression_to_s(string); // 将得到的表达式转化为后缀表达式 long long int calculate_from_postfix_expression(); // 依据后缀表达式计算值 private: vector<string…

题目 Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example, [1,1,2] have the following unique permutations: [ [1,1,2], [1,2,1], [2,1,1] ] 解答 C语言的实现以前总结过,请见 http://www.cnblogs.com/YuNanlong/p/6…

Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. 依旧是dfs,不过这次要注意的是排列不允许有重复的vector存在,那么在排列之前应该先排序,然后每次检查的时候,如…

Given a collection of integers that might contain duplicates, nums, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. 例子: If nums = [1,2,2], a solution is: […

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…

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…

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…

[1]LeetCode 136 Single Number 题意:奇数个数,其中除了一个数只出现一次外,其他数都是成对出现,比如1,2,2,3,3...,求出该单个数. 解法:容易想到异或的性质,两个相同的数异或为0,那么把这串数从头到尾异或起来,最后的数就是要求的那个数. 代码如下: class Solution { public: int singleNumber(vector<int>& nums) { ; ;i<nums.size();i++) sum ^= nums[i…

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…