PAT-A1015. Reversible Primes (20)

#include <iostream>#include <cstring>#include <cstdio>#include <cstdlib>#include <cmath>using namespace std;int n, radix;int reverse(int m){int t[10], cnt = 0, a = 0;while (m){t[cnt++] = m%radix;m /= radix;}for (int i = cnt-1; i >= 0; i--){int p = pow(radix, cnt-1-i)+0.5;a += t[i]*p;}return a;}int isPrime(int n){if (n <= 1)return 0;else{int sqr = sqrt(1.0*n);for (int i = 2; i <= sqr; i++){if (n%i == 0)return 0;}return 1;}}int main(){//freopen("in.txt", "r", stdin);//freopen("out.txt", "w", stdout);while (scanf("%d %d", &n, &radix) != EOF && n > 0){int r = 0;if (isPrime(n)){r = reverse(n);if (isPrime(r))printf("Yes\n");elseprintf("No\n");}elseprintf("No\n");}return 0;}