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…

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.…

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…

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 变长数组 求余法 维护行列 相似题目 参考资料 日期 题目地址:https://leetcode.com/problems/reshape-the-matrix/description/ 题目描述 In MATLAB, there is a very useful function called 'reshape', which can reshap…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址: https://leetcode.com/problems/random-point-in-non-overlapping-rectangles/description/ 题目描述: Given a list of non-overlapping axis-aligned rectangles rects, write a function pick which rando…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/random-pick-with-weight/description/ 题目描述: Given an array w of positive integers, where w[i] describes the weight of index i, write a function pickIndex which…

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 每次遍历索引 字典保存索引 蓄水池抽样 日期 题目地址:https://leetcode.com/problems/random-pick-index/description/ 题目描述 Given an array of integers with possible duplicates, randomly output the index of…

Search a 2D Matrix 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…

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…

原题 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…