九度1047（素数打表）

#include <functional>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <numeric>
#include <cstring>
#include <climits>
#include <cassert>
#include <complex>
#include <cstdio>
#include <string>
#include <vector>
#include <bitset>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <list>
#include <set>
#include <map>
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
typedef long long LL;
typedef double DB;
typedef unsigned uint;
typedef unsigned long long uLL;
/** Constant List .. **/
const int MOD = int(1e9)+7;
const int INF = 0x3f3f3f3f;
const LL INFF = 0x3f3f3f3f3f3f3f3fLL;
const DB EPS = 1e-9;
const DB OO = 1e20;
const DB PI = acos(-1.0); //M_PI;
/**BigNumber..**/
const int ten[4] = {1 , 10 , 100 , 1000};
const int maxl = 1000;
struct BigNumber{
    int d[maxl];
    BigNumber(string s){
        int len = s.size();
        d[0] = (len - 1) / 4 + 1;
        int i , j , k;
        for(i = 1 ; i < maxl ; i ++)    d[i] = 0;
        for(i = len - 1 ; i >= 0 ; i --){
            j = (len - i - 1) / 4 + 1;
            k = (len - i - 1) % 4;
            d[j] += ten[k] * (s[i] - '0');
        }
        while(d[0] > 1 && d[d[0]] == 0)    --d[0];
    }
    BigNumber(){
        *this = BigNumber(string("0"));
    }
    string toString(){
        string s("");
        int i , j , temp;
        for(i = 3 ; i >= 1 ; i --){
            if(d[d[0]] >= ten[i])
                break;
        }
        temp = d[d[0]];
        for(j = i ; j >= 0 ; j --){
            s = s + (char)(temp / ten[j] + '0');
            temp %= ten[j];
        }
        for(i = d[0] - 1 ; i > 0 ; i --){
            temp = d[i];
            for(j = 3 ; j >= 0 ; j --){
                s = s + (char)(temp / ten[j] + '0');
                temp %= ten[j];
            }
        }
        return s;
    }
}zero("0") , d , temp , midl[15];
BigNumber operator + (const BigNumber &a , const BigNumber &b){
    BigNumber c;
    c.d[0] = max(a.d[0] , b.d[0]);
    int i , x = 0;
    for(i = 1 ; i <= c.d[0] ; i ++){
        x = a.d[i] + b.d[i] + x;
        c.d[i] = x % 10000;
        x /= 10000;
    }
    while(x != 0){
        c.d[++c.d[0]] = x % 10000;
        x /= 10000;
    }
    return c;
}
BigNumber operator - (const BigNumber &a , const BigNumber &b){
    BigNumber c;
    c.d[0] = a.d[0];
    int i , x = 0;
    for(i = 1 ; i <= c.d[0] ; i ++){
        x = 10000 + a.d[i] - b.d[i] + x;
        c.d[i] = x % 10000;
        x = x / 10000 - 1;
    }
    while((c.d[0] > 1) && (c.d[c.d[0]] == 0))   -- c.d[0];
    return c;
}

const int maxn = 1000001;
bool is[maxn];

void f()
{
    memset(is , true , sizeof(is));
    is[0] = is[1] = false;
    int m = sqrt(maxn);
    for(int i = 2 ; i <= m ; i ++)
    {
        if(is[i])
        {
            for(int j = i * i ; j < maxn ; j += i)
                is[j] = false;
        }
    }
}

int main()
{
    #ifdef DoubleQ
    freopen("in.txt","r",stdin);
    #endif
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    int n;
    f();
    while(cin >> n)
    {
        if(is
)
            cout << "yes" << endl;
        else
            cout << "no" << endl;
    }
}