Given an array w of positive integers, where w[i] describes the weight of index i, write a function pickIndex which randomly picks an index in proportion to its weight. Note: 1 <= w.length <= 10000 1 <= w[i] <= 10^5 pickIndex will be called at…

原题链接在这里:https://leetcode.com/problems/random-pick-with-weight/ 题目: Given an array w of positive integers, where w[i] describes the weight of index i, write a function pickIndex which randomly picks an index in proportion to its weight. Note: 1 <= w.l…

Given an array w of positive integers, where w[i] describes the weight of index i, write a function pickIndex which randomly picks an index in proportion to its weight. Note: 1 <= w.length <= 10000 1 <= w[i] <= 10^5 pickIndex will be called at…

［抄题］: Given an array w of positive integers, where w[i] describes the weight of index i, write a function pickIndex which randomly picks an index in proportion to its weight. Note: 1 <= w.length <= 10000 1 <= w[i] <= 10^5 pickIndex will be cal…

1. 问题 给定一个权重数组w,w[i]表示下标i的权重,根据权重从数组中随机抽取下标. 2. 思路 这道题相当于 497. Random Point in Non-overlapping Rectangles的一个简化版. (1)可以先依次对每个下标的权重累加存起来(相当于概率分布中的分布累积函数CDF,Cumulative Distribution Function). (2)从 [1, 总权重] 中随机取一个数n,根据这个数在多个累加权重之间寻找合适的位置,即可完成题目要求的随机采样. (…

Given an array w of positive integers, where w[i] describes the weight of index i, write a function pickIndex which randomly picks an index in proportion to its weight. class Solution { Random random; int[] wSums; public Solution(int[] w) { this.rand…

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…

Given an array w of positive integers, where w[i] describes the weight of index i, write a function pickIndex which randomly picks an index in proportion to its weight. Note: 1 <= w.length <= 10000 1 <= w[i] <= 10^5 pickIndex will be called at…

Given a blacklist B containing unique integers from [0, N), write a function to return a uniform random integer from [0, N) which is NOT in B. Optimize it such that it minimizes the call to system’s Math.random(). Note: 1 <= N <= 1000000000 0 <=…

Question 710. Random Pick with Blacklist Solution 题目大意:给一个N,表示一个范围[0,N),给一个黑名单列表blacklist,其中blacklist中的元素在[0,N)范围内,调用pick方法的时候随机返回一个数,这个数满足 在[0,N)范围 不在blacklist内 要随机 思路:构造一个集合M,该M是 [0,N) - blacklist 的一个集合,调用pick时,返回[0,M)的一个随机数并根据这个随机数从集合M中取数即可. Java实…