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…

519. 随机翻转矩阵 题中给出一个 n 行 n 列的二维矩阵 (n_rows,n_cols),且所有值被初始化为 0.要求编写一个 flip 函数,均匀随机的将矩阵中的 0 变为 1,并返回该值的位置下标 [row_id,col_id]:同样编写一个 reset 函数,将所有的值都重新置为 0.尽量最少调用随机函数 Math.random(),并且优化时间和空间复杂度. 注意: 1.1 <= n_rows, n_cols <= 10000 0 <= row.id < n_rows…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/random-flip-matrix/description/ 题目描述: 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…

1. 问题 给定一个全零矩阵的行和列,实现flip函数随机把一个0变成1并返回索引,实现rest函数将所有数归零. 2. 思路 拒绝采样 (1)先计算矩阵的元素个数(行乘以列),记作n,那么[0, n-1]相当于矩阵下标对应的一维索引. (2)用一个arrays数组存放矩阵元素为1的索引.每次从 [0, n-1]取数,这个数可以表示矩阵元素的索引,如果取的数已经在这个数组里,说明这个索引对应的矩阵元素已经被flip为1了,则放弃,继续取数,直到取到的数不在数组里(对应的矩阵元素为0),就把取到的…

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…

You are playing the following Flip Game with your friend: Given a string that contains only these two characters: + and -, you and your friend take turns to flip two consecutive "++" into "--". The game ends when a person can no longer…

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…

题目如下: 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.…

Given an array of integers with possible duplicates, randomly output the index of a given target number. You can assume that the given target number must exist in the array. Note: The array size can be very large. Solution that uses too much extra sp…

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,…

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…

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`…

You are playing the following Flip Game with your friend: Given a string that contains only these two characters: + and -, you and your friend take turns to flip twoconsecutive "++" into "--". The game ends when a person can no longer…

Spiral Matrix II 螺旋矩阵 Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example,Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ] 看博客园有人面试碰到过这个问题,长篇大论看得我头晕…

1.Image.open(image_path)  进行图片的打开 参数说明:image_path 表示图片的路径 2. ImageEnhance.Brightness(image)  # 进行图片的亮度变化 enhance_image.enhance(0.3) 参数说明:image表示需要进行亮度变化的图片 3. ImageEnhance.Contrast(image) enhance_image.enhance(0.2) 参数说明:image表示需要进行饱和度变化的图片 4.enhance_…

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example, Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ]] 解题思路: 参考Java for LeetCode 054 Spiral Matrix,修改下…

//20160518 Math类常用方法 练习 package MyPackage; public class MathDemo {//定义主类和main方法 public static void main(String[] args) { System.out.println(Math.sqrt(16));// Math类常用方法:求平方根 System.out.println(Math.pow(2, 3));// Math类常用方法:多少的多少次方 System.out.println(Ma…

import random # print(random.random()) # 随机浮点数,默认取0-1,不能指定范围# print(random.randint(1, 20)) # 随机整数,顾头顾尾# print(random.choice('sdfsd233')) # 随机取一个元素# print(random.sample('hello234234史蒂夫34', 4))#从序列中随机取几个元素,返回是一个list # f =random.uniform(1, 9) # 随机取浮点数,可…

[LeetCode]01 Matrix 解题报告 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/01-matrix/#/description 题目描述: Given a matrix consists of 0 and 1, find the distance of the nearest 0 for each cell. The distance between two adjacent cells is 1. Example:…

LeetCode 25 k组一个翻转链表 TITLE 示例 1: 输入:head = [1,2,3,4,5], k = 2 输出:[2,1,4,3,5] 示例 2: 输入:head = [1,2,3,4,5], k = 3 输出:[3,2,1,4,5] 示例 3: 输入:head = [1,2,3,4,5], k = 1 输出:[1,2,3,4,5] 示例 4: 输入:head = [1], k = 1 输出:[1] (PS:还是加上title吧不然太难受了) 前言:LeetCode难度hard…

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…

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…

Given a list of non-overlapping axis-aligned rectangles rects, write a function pick which randomly and uniformily picks an integer point in the space covered by the rectangles. Note: An integer point is a point that has integer coordinates. A point …

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen. Follow up: What if the linked list is extremely large and its length is unknown to you? Could you solve this effi…

In MATLAB, there is a very useful function called 'reshape', which can reshape a matrix into a new one with different size but keep its original data. You're given a matrix represented by a two-dimensional array, and two positive integers r and c rep…

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example,Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ] 题目标签:Array 这道题目和之前的螺旋矩阵几乎没有区别,而且更简单.同样按照螺旋矩阵的特性…

In MATLAB, there is a very useful function called 'reshape', which can reshape a matrix into a new one with different size but keep its original data. You're given a matrix represented by a two-dimensional array, and two positive integers r and c rep…

Given a matrix consists of 0 and 1, find the distance of the nearest 0 for each cell. The distance between two adjacent cells is 1. Example 1: Input: 0 0 0 0 1 0 0 0 0 Output: 0 0 0 0 1 0 0 0 0 Example 2: Input: 0 0 0 0 1 0 1 1 1 Output: 0 0 0 0 1 0…