Java实现 洛谷 P1217 [USACO1.5]回文质数 Prime Palindromes

import java.util.Scanner;
 
public class Main {
	private static Scanner cin;
	
	public static void main(String args[]) throws Exception {
		cin = new Scanner(System.in);
		int a = cin.nextInt();
		int b = cin.nextInt();
		for (int i=a; i<=b; i++) {
			//如果可以被2、3、5整除，必然不满足条件
			if(i!= 2 && i!=3 && i!=5 && (i%2==0 || i%3==0 || i%5==0)) {
				continue;
			}
			if(isPalindrome(i)) {
				if(isPrime(i)) {
					System.out.println(i);
				}
			}
		}
	}
	
	public static boolean isPalindrome(int n) {
		int x = n;
		int y = 0;
		boolean ret = false;
		while(x!=0) {
			y = y*10 + x%10;
			x = x/10;
		}
		
		if(y == n) {
			ret = true;
		}
		return ret;
	}
	public static boolean isPrime(int n) {
		boolean ret = true;
		if ( n == 1 || n == 2 || n == 3) {
			ret = true;
		}else {
			for(int i = 2; i<=Math.sqrt(n);i++) {
				if(n%i == 0){
					ret = false;
					break;
				}
			}
		}
		return ret;
	}
}