给定一个 n × n 的二维矩阵表示一个图像. 将图像顺时针旋转 90 度. 说明: 你必须在原地旋转图像,这意味着你需要直接修改输入的二维矩阵.请不要使用另一个矩阵来旋转图像. 示例 : 给定 matrix = [ [1,2,3], [4,5,6], [7,8,9] ], 原地旋转输入矩阵,使其变为: [ [7,4,1], [8,5,2], [9,6,3] ] 思路: 1.我的思路是重外围四个角往里面缩小,所以第一次循环的个数可以减半,减少循环次数 2.第二个循环依次处理四个角位置的互换,/*…

前言 这几天在修复一个web问题时,需要捕获Mac触摸板双指事件(上.下.左.右.放大.缩小),但发现并没有现成的轮子,还是要自己造. 例如:jquery.mousewheel.js(添加跨浏览器的鼠标滚轮支持), 给得太简单,没有处理Mac双指行为,所以不能用. 目标 获取Mac触摸板双指行为,具体有两个,一个是实时拖动路线,二是手势(上.下.左.右.放大.缩小). 难点 双指行为只会触发mousewheel事件,其他什么的touch,mouse都不会触发,只能从这个下手. 双指特性 1.在快…

开个新坑,leetcode上面做题目.下面是题目描述: <!-- 给定一个字符串,请你找出其中不含有重复字符的最长子串的长度. 示例 1: 输入: "abcabcbb" 输出: 3 解释: 因为无重复字符的最长子串是 "abc",所以其长度为 3. 示例 2: 输入: "bbbbb" 输出: 1 解释: 因为无重复字符的最长子串是 "b",所以其长度为 1. 示例 3: 输入: "pwwkew" 输出…

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted in ascending from left to right. Integers in each column are sorted in ascending from top to bottom.…

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted in ascending from left to right. Integers in each column are sorted in ascending from top to bottom.…

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the last integer of the previous ro…

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the last integer of the previous ro…

问题描述: 求一个矩阵中最大的二维矩阵(元素和最大).如: 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 中最大的是: 4 5 9 10   分析: 2*2子数组的最大和.遍历求和,时间复杂度为O(mn).   代码实现: // 35.cc #include <iostream> #include <climits> using namespace std; ], int m, int n) { int max_sum = INT_MIN; int sum; ; i…

安装qrcode库和PIL库 在命令行中分别输入pip install qrcode 和pip install pillow 导入库格式如下: import PIL import qrcode 下面以生成一个带图标的二维码为例 from PIL import Image import qrcode qr = qrcode.QRCode( version=2, error_correction=qrcode.constants.ERROR_CORRECT_H, box_size=10, borde…

11.6 Given an M x N matrix in which each row and each column is sorted in ascending order, write a method to find an element. LeetCode上的原题,请参见我之前的博客Search a 2D Matrix 搜索一个二维矩阵和Search a 2D Matrix II 搜索一个二维矩阵之二. class Solution { public: bool findElemen…