问题: 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?   分析: 二维数组a[n][n]顺时针旋转90度,要解决这个问题,无疑,第一件事儿就是找规律. 当n=1时,不用动了. 当n=2时, 旋转之后变为 有: a[0][0] = a[1][0] a[1][0] =…

public class RotateImage { public void rotate(int[][] matrix) { if(matrix.length == 1 && matrix[0].length == 1) { return; } int n = matrix.length; for(int i = 0; i < n-1; i ++) { for(int j = i; j < n-1-i; j ++) { int temp = matrix[i][j]; mat…

题意: 将一个n*n的矩阵顺时针旋转90度. 思路: 都是差不多的思路,交换3次也行,反转再交换也是行的. class Solution { public: void rotate(vector<vector<int>>& matrix) { , n=matrix.size(); <n) { ; j++) { swap(matrix[n-j-][i],matrix[n-i-][n-j-]); swap(matrix[n-i-][n-j-],matrix[j][n-i-…

/** * 将n*n矩阵顺时针旋转90度 * @param mat * @param n 矩阵的阶数 * @date 2016-10-7 * @author shaobn */ public static void rotateMatrix(int[][] mat,int n){ int[][] mat_rotate = new int[n][n]; for(int i = 0;i<n;i++){ for(int j = 0;j<n;j++){ mat_rotate[j][n-1-i]=mat…

STL中的list就是一双向链表,可高效地进行插入删除元素. List 是 C++标准程式库 中的一个 类 ,可以简单视之为双向 连结串行 ,以线性列的方式管理物件集合.list 的特色是在集合的任何位置增加或删除元素都很快,但是不支持随机存取.list 是 C++标准程式库 提供的众多容器(container)之一,除此之外还有 vector .set.map.…等等.list 以模板方式实现(即泛型),可以处理任意型别的变量,包括使用者自定义的资料型态,例如:它可以是一个放置整数(int)型…

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? Hide Tags Array   一题严格的数组逻辑操作问题,考虑认真就好,思路:   1 2 3 1 3 4 4 2 2 4 4 3 1 3 2 1 如上表,一共有两圈,对于n 来说,圈数为(n+1)/2,从外圈到内圈,…

48. Rotate Image     Total Accepted: 69437 Total Submissions: 198781 Difficulty: Medium You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). 显然的,矩阵旋转. 这里我是多开一个数组来直接赋值,没有原地翻转. 或许原地翻转能更快. package leetcode.…

原题地址:https://oj.leetcode.com/problems/rotate-image/ 题意: 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? 解题思路:先将矩阵转置,然后将矩阵的每一行翻转,就可以得到所要求的矩阵了. 代码: class Solution…

1. Question 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 matri…

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…

Given a list, rotate the list to the right by k places, where k is non-negative. For example:Given 1->2->3->4->5->NULL and k = 2,return 4->5->1->2->3->NULL. 这道旋转链表的题和之前那道Rotate Array 旋转数组 很类似,但是比那道要难一些,因为链表的值不能通过下表来访问,只能一个一个的…

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? 在计算机图像处理里,旋转图片是很常见的,由于图片的本质是二维数组,所以也就变成了对数组的操作处理,翻转的本质就是某个位置上数移动到另一个位置上,比如用一个简单的例子来分析: 1  2  3 7  4  1 4  5  6 -…

Given a list, rotate the list to the right by k places, where k is non-negative. For example: Given 1->2->3->4->5->NULL and k = 2, return 4->5->1->2->3->NULL. 原题链接:https://oj.leetcode.com/problems/rotate-list/ 得到链表长度.链表指向尾节点,…

Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place. click to show follow up. Follow up: Did you use extra space?A straight forward solution using O(mn) space is probably a bad idea.A simple improvement uses O…

Given 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 return [1,2,3,6,9,8,7,4,5]. 题目标签:Array 这道题目给了我们一个矩阵,…

We have a two dimensional matrix A where each value is 0 or 1. A move consists of choosing any row or column, and toggling each value in that row or column: changing all 0s to 1s, and all 1s to 0s. After making any number of moves, every row of this…

原题地址:https://oj.leetcode.com/problems/rotate-list/ 题意: Given a list, rotate the list to the right by k places, where k is non-negative. For example:Given 1->2->3->4->5->NULL and k = 2,return 4->5->1->2->3->NULL. 解题思路:循环右移一条链表…

Rotate Array 本题目收获: 题目: 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]. 思路: 我的思路:新建一个数组存放旋转后的内容,但是怎么把原数组的内容存放在数组中,不清楚. leetcode/discuss思路: 思路一:新建数组,复制原…

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? 方法一:常规思路: 将图片分为 行数/2 层,然后一层层进行旋转,由外到里.在这个过程中,比较关键的是下标的处理.可从n=3时得出一定的规律.每次旋转时,分析替换的元素对的下标和行.列的关系.如 i=0.j=0时 1:[0]…

On a 2 dimensional grid with R rows and C columns, we start at (r0, c0) facing east. Here, the north-west corner of the grid is at the first row and column, and the south-east corner of the grid is at the last row and column. Now, we walk in a clockw…

Given an integer n, generate a square matrix filled with elements from 1 to n^2 in spiral order. For example,Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ] 与 54. Spiral Matrix 类似,这次给定一个整数n,以螺旋顺序填充元素到n^2…

这是小川的第384次更新,第412篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第246题(顺位题号是1030).我们给出一个矩阵,其中R行和C列具有整数坐标(r,c)的单元格,其中0 <= r <R且0 <= c <C. 另外,我们在该矩阵中给出了一个坐标为(r0,c0)的单元格. 返回矩阵中所有单元格的坐标,按照它们从(r0,c0)到最小距离到最大距离的距离进行排序.这里,两个单元格(r1,c1)和(r2,c2)之间的距离是曼哈顿距离,|r1 -…

Given an array of integers A and let n to be its length. Assume Bk to be an array obtained by rotating the array A k positions clock-wise, we define a "rotation function" F on A as follow: F(k) = 0 * Bk[0] + 1 * Bk[1] + ... + (n-1) * Bk[n-1]. Ca…

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? Do not think too much about this problem, don't be scared by the "Matrix" word. This problem can be done i…

in place交换 如果是k步,那么就是把后面k个放到前面了嘛. 我们先把整个数组reverse,然后把前面的reverse回来,再把后面的reverse回来 对于AB我们要通过reverse操作得到BA 那么先把AB reverse一次得到reverse(B)reverse(A) 然后再把reverse(B),reverse(A)分别reverse一次就得到了BA class Solution { public: void rotate(int nums[], int n, int k) {…

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? 原题链接(点我) 解题思路 顺时针方向旋转数组90°.这个题也是个没啥意思的题,自己画绘图,找找规律.就出来了.我举一个n=4的样例还说明下规律: 通过图能够看出A[0][0] = A[3][0],.....从这些中…

给定一个矩阵,把零值所在的行和列都置为零.例如: 1 2 3 1 3 1 1 1 操作之后变为 1 3 0 0 0 1 1 方法1: 赋值另存一个m*n的矩阵,在原矩阵为零的值相应置新的矩阵行和列为零.额外空间为O(m*n). 方法2: 两个数组,bool[m] 和 bool[n] 分别存某行有零,后者某列有零.之后根据数组值将原矩阵相应位置置零.额外空间O(m + n). class Solution { public: void setZeroes(vector<vector<int>…

We are stacking blocks to form a pyramid. Each block has a color which is a one letter string, like `'Z'`. For every block of color `C` we place not in the bottom row, we are placing it on top of a left block of color `A` and right block of color `B`…

We are given two strings, A and B. A shift on A consists of taking string A and moving the leftmost character to the rightmost position. For example, if A = 'abcde', then it will be 'bcdea' after one shift on A. Return True if and only if A can becom…

You are given the number of rows n_rows and number of columns n_cols of a 2D binary matrix where all values are initially 0. Write a function flip which chooses a 0 value uniformly at random, changes it to 1, and then returns the position [row.id, co…