Reverse Integer Reverse digits of an integer. Example1: x = 123, return 321Example2: x = -123, return -321 click to show spoilers. SOLUTION 1: 注意越界后返回0.先用long来计算,然后,把越界的处理掉. public class Solution { public int reverse(int x) { long ret = 0; while (x !…

Combination Sum Combination Sum Total Accepted: 25850 Total Submissions: 96391 My Submissions Question Solution Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The…

全排列问题.经常使用的排列生成算法有序数法.字典序法.换位法(Johnson(Johnson-Trotter).轮转法以及Shift cursor cursor* (Gao & Wang)法. [题目] Given 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], [2…

以前从来没有写过解题报告,只是看到大肥羊河delta写过不少.最近想把写博客的节奏给带起来,所以就挑一个比较容易的题目练练手. 原题链接 https://leetcode.com/problems/course-schedule/ 题目大意 有n个课程,编号分别是0到n-1.我们的目标是修完所有课程.然而有些课程有前置课程的,我们必须修完前置课程才能修该门课程.题目给了我们课程之间的前置关系,让我们判断是否能修完所有课程. 题目原型 这个题目的描述简单粗暴,我们不难发现,其实是给了我们一个有向图…

Sort ColorsGiven an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue. Here, we will use the integers 0, 1, and 2 to represent the color red, wh…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 数组转整数再转数组 模拟加法 日期 题目地址:https://leetcode.com/problems/add-to-array-form-of-integer/ 题目描述 For a non-negative integer X, the array-form of X is an array of its digits in left to r…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 解题方法 二进制字符串翻转 位运算 日期 题目地址:https://leetcode.com/problems/reverse-bits/description/ 题目描述 Reverse bits of a given 32 bits unsigned integer. Example: Input: 43261596 Output: 964176192 Explan…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 日期 题目地址:https://leetcode.com/problems/complement-of-base-10-integer/ 题目描述 Every non-negative integer N has a binary representation. For example, 5 can be represented as "101&qu…

题目要求 Roman numerals are represented by seven different symbols: I, V, X, L, C, Dand M. Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For example, two is written as II in Roman numeral, just two one's added together. Twelve is written as, XII, whi…

题目要求 Every non-negative integer N has a binary representation.  For example, 5 can be represented as "101" in binary, 11 as "1011" in binary, and so on.  Note that except for N = 0, there are no leading zeroes in any binary representat…