1015 Reversible Primes
作者:互联网
1015 Reversible Primes
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.
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 2
23 10
-2
Sample Output:
Yes
Yes
No
#include <bits/stdc++.h>
using namespace std;
bool judge(int x)
{
if(x<=1) return false;
int sqr=(int)sqrt(1.0*x);
for(int i=2;i<=sqr;i++){
if(x%i==0) return false;
}
return true;
}
int main()
{
int n,d;
while(scanf("%d",&n)!=EOF){
if(n<0) break;
cin>>d;
if(judge(n)==false){
cout<<"No\n";
continue;
}
int ans[100],num=0,sum=0,h=1;
do{
ans[num++]=n%d;
n/=d;
}while(n!=0);
for(int j=num-1;j>=0;j--){
sum+=ans[j]*h;
h*=d;
}
if(judge(sum)==true) cout<<"Yes\n";
else cout<<"No\n";
}
return 0;
}
标签:prime,int,reversible,system,Reversible,judge,1015,Primes,Yes 来源: https://blog.csdn.net/xuexiwd/article/details/113755956