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…

Question 398. Random Pick Index Solution 思路:重点是如果数据中有多个数target相等,要从这些数中随机取一个,根据例题 假设输入是: int[] nums = new int[]{1, 2, 3, 3, 3}; int target = 3; 模拟: 1 != target pass 2 != target pass 3 == target pick的概率 nextInt(1)==0的概率 1,返回这个index的概念是1 - 1/3 -1/3 = 1…

［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 sp…

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…

我是链接 看到这道题,想到做的几道什么洗牌的题,感觉自己不是很熟,但也就是rand()函数的调用,刚开始用map<int, vector<int >>来做,tle,后来就想着直接保存nums数组,和每个元素的数目,然后先生成一个随机的第几个target,然后从nums里面再找这个index,交了,就过了,有套路么? class Solution { public: map<int, int> m; vector<int> num; Solution(vect…

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(…

给定一个可能含有重复元素的整数数组,要求随机输出给定的数字的索引. 您可以假设给定的数字一定存在于数组中.注意:数组大小可能非常大. 使用太多额外空间的解决方案将不会通过测试.示例:int[] nums = new int[] {1,2,3,3,3};Solution solution = new Solution(nums);// pick(3) 应该返回索引 2,3 或者 4.每个索引的返回概率应该相等.solution.pick(3);// pick(1) 应该返回 0.因为只有nums[…

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 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…