素数的筛选

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<vector>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<list>
#include<string>
#include<cmath>
#include<sstream>
#include<ctime>
using namespace std;
#define _PI acos(-1.0)
#define INF 1 << 10
#define esp 1e-6
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int,int> pill;
/*===========================================
===========================================*/
#define MAX_SIZE 100000000 + 1
int vis[MAX_SIZE];
LL Get_PrimeNumber(int MAXD){
    memset(vis,0,sizeof(vis));
    LL ans = 0;
    for(LL i = 2 ; i < MAXD ; i++)if(!vis[i]){ /*如果只是单纯的筛选素数 这里 i <= sqrt(MAXD) */
        ans ++;
        for(LL j = i * i ; j < MAXD ; j += i)
            vis[j] = 1;
    }
    return ans;
}
int main(){
    int T;
    int text[] = {100,1000,10000,100000,1000000,10000000,100000000};
    for(int i = 0 ; i < 7 ; i ++){
        LL ans = Get_PrimeNumber(text[i] + 1);
        printf("[1 ~ %d ]：%I64d\n",text[i],ans);
    }
    return 0;
}