hdu_2012 素数判定

import java.util.Scanner;/** * Created by feyman1120 on 2017/11/24. */public class Main {    /*如果一个数不能被2到它的平方根整除，则说明为一个素数*/    public static boolean isPrime(int x){        int y = (int)Math.sqrt(x);        for (int i = 2; i <= y; ++i){            if (x % i == 0){                return false;            }        }        return true;    }    public static void main(String[] args) {        Scanner scan = new Scanner(System.in);        while (scan.hasNext()) {            int st = scan.nextInt();            int ed = scan.nextInt();            if (0 == st + ed){                break;            }            /*交换两个数*/            if (st > ed) {                st = st ^ ed;                ed = st ^ ed;                st = st ^ ed;            }            boolean flg = false;            for (int i = st; i <= ed; ++i){                int y = i * i + i + 41;                if (!isPrime(y)){                    flg = true;                    break;                }            }            if (flg){                System.out.println("Sorry");            }            else {                System.out.println("OK");            }        }    }}