leetcode - 48. Rotate Image - Medium descrition You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Note: You have to rotate the image in-place, which means you have to modify the input 2D matrix direct…

leetcode - 39. Combination Sum - Medium descrition Given a set of candidate numbers (C) (without duplicates) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same repeated number may be chosen from…

leetcode - 31. Next Permutation - Medium descrition Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not possible, it must rearrange it as the lowest possible…

You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Follow up:Could you do this in-place? 题目标签:Array 这道题目给了我们一个n * n的矩阵,让我们旋转图片.题目要求in-place,所以就不能用额外的空间了.一开始自己写了一个很原始的方法,结果虽然通过,但是速度太慢.只好去看看别人的方法,看完觉得,自己…

You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Note: You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the…

题目链接: https://leetcode.com/problems/rotate-image/?tab=Description   Problem:给定一个n*n的二维图片,将这个二维图片按照顺时针旋转90°   求解过程:   参考链接 https://discuss.leetcode.com/topic/9744/ac-java-in-place-solution-with-explanation-easy-to-understand   求解过程如下所示:     首先对矩阵进行按照对…

1 题目 You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Follow up:Could you do this in-place? 2 思路 使用辅助空间比较简单. 不使用辅助空间,想了半天,没想出来.. 看别人的代码,原来是要翻转两次.. 3 代码 public void rotate(int[][] matrix) { // 使用多余空间的…

Rotate Image You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Follow up: Could you do this in-place? 思路:事实上就是旋转数组.没有什么难度.代码例如以下: public class Solution { public void rotate(int[][] matrix) { int[][] a…

leetcode-54. Spiral Matrix - Medium descrition GGiven a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order. For example, Given the following matrix: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] You should ret…

You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Note: You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the…

题目大意:给一个矩阵,将其按顺时针旋转90°. 题目分析:通法是先将矩阵转置,然后再反转每一行,或者是先反转每一列,然后再将其转置.I just want to say"It's amazing!".(forgivig my poor English!) 代码如下(代码怎么写已经不重要了!): class Solution { public: void rotate(vector<vector<int>>& matrix) { int r=matrix.…

题目: You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Note: You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do…

题意 原地顺时针翻转一个 n*n 的矩阵 图解 下面例子中用 5*5 矩阵做示例,如下图,我们要把该矩阵顺时针翻转90度,并且不能使用另外的矩阵空间来暂存数据,而是原地改变矩阵中数值. 我的想法是这样的:找出翻转的下标变换规律,找出需要变换的位置,将与该位置有关的四个方法(left, top, right, bottom)一次性交换值. 如下图: 首先我从最外围入手,其实整个外围的变化,可以以第一行的 (0, n-2)坐标的元素为基础开始变化,其他三个方向是跟它有关的需要同时变换的元素: 同理,…

Given a linked list, rotate the list to the right by k places, where k is non-negative. Example 1: Input: 1->2->3->4->5->NULL, k = 2 Output: 4->5->1->2->3->NULL Explanation: rotate 1 steps to the right: 5->1->2->3-&g…

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 48: Rotate Imagehttps://leetcode.com/problems/rotate-image/ You are given an n x n 2D matrix representing an image.Rotate the image by 90 degrees (clockwise).Could you do this in-place? ===…

Question 48. Rotate Image Solution 把这个二维数组(矩阵)看成一个一个环,循环每个环,循环每条边,每个边上的点进行旋转 public void rotate(int[][] matrix) { int n = matrix.length; for (int i = 0; i < n / 2; i++) { change(matrix, i); } } private void change(int[][] matrix, int i) { int n = mat…

leetcode - 40. Combination Sum II - Medium descrition Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. Each number in C may only be used once in the combinat…

目录 # 前端与算法 leetcode 48. 旋转图像 题目描述 概要 提示 解析 解法一:转置加翻转 解法二:在单次循环中旋转 4 个矩形 算法 传入测试用例的运行结果 执行结果 GitHub仓库 # 前端与算法 leetcode 48. 旋转图像 题目描述 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 1: 给定 matrix = [ [1,2,3],…

原题链接 直接贴代码,这道题是 search in rotated sorted array leetcode 的前面部分! class Solution { public: int findMin(vector<int>& nums) { if (nums.empty()) ; , nums.size()-);//好神奇,第二个参数无论减或者不减1,都不影响该题的结果 ) ; return nums[res]; } int find(vector<int>& nu…

目录 题目链接 注意点 解法 小结 题目链接 Find First and Last Position of Element in Sorted Array - LeetCode 注意点 nums可能为空 时间复杂度为O(logn) 解法 解法一:最普通的二分搜索,先找到一个target,然后向两边拓展. class Solution { public: int binarySearch(vector<int>& nums, int target) { int left = 0,rig…

一.题目说明 题目是48. Rotate Image,简而言之就是矩阵顺时针旋转90度.不允许使用额外的矩阵. 经过观察(写一个矩阵,多看几遍就知道了),旋转90度后: 第1行变为len-1列(最后一列),第i行变为 len-i-1列最终达到(i,j)-->(j,len-i-1) 知道规律后,做法就比较简单了,可以先上下行交换,再对角交换: (i,j)-->(len-i-1,j)-->(j,len-i-1) 也可以先对角交换,再左右列交换: (i,j)-->(j,i)-->(…

697. Degree of an Array - LeetCode Question 697. Degree of an Array - LeetCode Solution 理解两个概念: 数组的度:[1,2,2,3,1]这个数组,去重后的元素为[1,2,3],每个元素在原数组中重复的次数分别是221,数组的度就是元素最大重复次数,这个数组中元素最大重复次数就是2 连续子数组:和字符串中的了串概念类似,数组元素顺序保持不变,取其中一部分,该题就是求在度相同的情况下最小连续子数组的长度 思路:数…

Rotate an array of n elements to the right by k steps. For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4]. Note:Try to come up as many solutions as you can, there are at least 3 different ways to solve this pro…

leetcode - 34. Search for a Range - Medium descrition Given an array of integers sorted in ascending order, find the starting and ending position of a given target value. Your algorithm's runtime complexity must be in the order of O(log n). If the ta…

leetcode - 33. Search in Rotated Sorted Array - Medium descrition Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). You are given a target value to search.…

Given an array, rotate the array to the right by k steps, where k is non-negative. Example 1: Input: [1,2,3,4,5,6,7] and k = 3 Output: [5,6,7,1,2,3,4] Explanation: rotate 1 steps to the right: [7,1,2,3,4,5,6] rotate 2 steps to the right: [6,7,1,2,3,4…

Difficulty:medium  More:[目录]LeetCode Java实现 Description https://leetcode.com/problems/rotate-image/ You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Note: You have to rotate the image in-place, which…

Rotate an array of n elements to the right by k steps. For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4]. 解题思路: JAVA实现如下: public void rotate(int[] nums, int k) { k%=nums.length; k=nums.length-k; int[] nums2=ne…

Rotate Array Rotate an array of n elements to the right by k steps. For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4]. Note: Try to come up as many solutions as you can, there are at least 3 different ways to…

Rotate an array of n elements to the right by k steps. For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4]. Note:Try to come up as many solutions as you can, there are at least 3 different ways to solve this pro…