PAT 1015. Reversible Primes (20)

//1015. Reversible Primes (20)
//acc
#include <iostream>
using namespace std;

int Prime( int x )
{
	int i;

	if(x==1)
		return 0;

	for (i =2;i<=x/2;i++)
	{
		if (x%i == 0)
		{
			return 0;
		}
	}
	return 1;
}

int main()
{
	int N, D;
	int a[15];
	bool flag = true;
	int i = 0;
	int len;
	int rn;
	while((cin>>N)!=NULL)
	{
		if (N <0 )
		{
			break;
		}
		cin>>D;
		
		if (!(Prime(N)))	
		{
			cout<<"No\n";
		}
		else
		{
			//计算多进制的值
			i = 0;
			while(N!=0)
			{
				a[i++] = N%D;
				N = N/D;
			}
			len = i;
			rn = 0;
			for(i=0;i<len-1;i++)
			{
				rn+= a[i];
				rn*=D;
			}
			rn += a[i];

			if(Prime(rn))
			{
				cout<<"Yes\n";
				continue;
			}
			else
			{
				cout<<"No\n";
				continue;
			}
		}
			

	}

	return 0;
}