CLamb的博客

Stacks Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/262144 K (Java/Others) Total Submission(s): 226 Accepted Submission(s): 39 Problem Description There are N stacks, numbered from 1 to N. Initially, the i-th stack only contains a numbe

素数筛 转载：https://blog.youkuaiyun.com/dy416524/article/details/86431057 枚举所有小于数，看是否它能整除其他自然数，但实际上只需要枚举根号次。 bool Is_prime(int n) { for(int i=1;i*i<=n;++i) { if(n%i==0) return false; } return true; } •埃氏筛：做法其实很简单，首先将2到n范围内的整数写下来，其中2是最小的素数。