NowCoder小定律

题目：https://www.nowcoder.com/pat/2/problem/259

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 10005;
int f[maxn];

void db(){
    memset(f, 0, sizeof(f));
    f[1] = 1;
    f[2] = 0;
    f[3] = 0;
    for (int i = 3; i < maxn; i++){
        if (f[i] == 0){
            int j = i+i;
            while (j < maxn){
                f[j] = 1;
                j += i;
            }
        }
    }
}

int main(){
    std:ios::sync_with_stdio(false);
    int x, y;
    db();
    while ((cin >> x >> y) && (x||y)){
        int n;
        bool ok = true;
        for (int i = x; i <= y; i++){
            n = i *i + i + 41;
            if (f[n] == 1){
                ok = false;
                break;
            }
        }
        if (ok){
            cout << "OK" << endl;
        }
        else
            cout << "Sorry" << endl;
    }
//    system("pause");
    return 0;
}