384. Shuffle an Array random.nextInt(n) 返回[0, n) 的随机数,故要+1: class Solution { private int[] nums; private Random random; public Solution(int[] nums) { this.nums = nums; random = new Random(); } /** Resets the array to its original configuration and re…
蓄水池抽样——<编程珠玑>读书笔记 382. Linked List Random Node 398. Random Pick Index 从n个数中随机选取m个 等概率随机函数面试题总结 问题:如何随机从n个对象中选择一个对象,这n个对象是按序排列的,但是在此之前你是不知道n的值的. 思路:如果我们知道n的值,那么问题就可以简单的用一个大随机数rand()%n得到一个确切的随机位置,那么该位置的对象就是所求的对象,选中的概率是1/n. 但现在我们并不知道n的值,这个问题便抽…
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…
随机返还target值的坐标(如果存在多个target). 不太明白为什么这个题是M难度的. 无非是要么弄TABLE之类的,开始麻烦点,但是pick的时候直接PICK出来就行了. 要么开始简单点,都存了,选的时候再随机选. 前者各种溢出..貌似memory在leetcode比较值钱..就用后者 public class Solution { int[] nums; public Solution(int[] nums) { this.nums = nums; } public int pick(…
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…
［抄题］: 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 ext…
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 spa…
