1015. Reversible Primes (20)

1015. Reversible Primes (20)

AReversible primeIn 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 (<105) and D (1 <D <= 10), you are supposed to tell if N is a reversible prime with radix D.

Input Specification:

The input file consists of several test cases. Each case occupies a line which contains two integers N and D. The input is finished by a negative N.

Output Specification:

For each test case, print in one line "Yes" if N is a reversible prime with radix D, or "No" if not.

Sample Input:
73 10
23 22
3 10
-2
Sample Output:
Yes
Yes
No

#include 
 
  #include #include 
  
   using namespace std;bool isPrime(int x) {    if(x < 2) {        return false;    }    if(x == 2 || x == 3) {        return true;    }    for(int i=2; i*i<=x; i++) {        if(x % i == 0) {            return false;        }    }    return true;}int main() {    int n, d;    while(cin>>n) {        if(n < 0) {            break;        } else {            cin>>d;            if(isPrime(n)) {                queue
   
     q;                while(n!=0) {                    q.push(n%d);                    n /= d;                }                int reverse = 0;                while(!q.empty()) {                    reverse=reverse*d;                    reverse=reverse+q.front();                    q.pop();                }                if(isPrime(reverse)) {                    cout<<"Yes"<