1015 Reversible Primes (20 point(s))

1015 Reversible Primes (20 point(s))

A reversible prime in any number system is a prime whose "reverse" in that number system is also a prime. For example in the decimal system 73 is a reversible prime because its reverse 37 is also a prime.

Now given any two positive integers N (<10​5​​) and D (1<D≤10), you are supposed to tell if N is a reversible prime with radix D.

Example:

#include<iostream>
#include<queue>

using namespace std;

bool isPrime(int num)
{
    if(num <= 1) return false;
    for(int i = 2; i*i <= num; i++)
        if(num % i == 0) return false;
    return true;
}

int main()
{
    while(1) {
        int N, K;
        cin >> N;
        if(N < 0) break;
        cin >> K;
        if(isPrime(N)) {
            queue<int> digits;
            while(N) {
                digits.push(N % K);
                N /= K;
            }
            while(!digits.empty()) {
                N *= K;
                N += digits.front();
                digits.pop();
            }
            if(isPrime(N)) {
                cout << "Yes\n";
                continue;
            }
        }
        cout << "No\n";
    }
}

思路：

利用队列，将数字翻转，再判断是否素数。