PAT 1015 Reversible Primes
1015. Reversible Primes (20)
时间限制
400 ms
内存限制
65536 kB
代码长度限制
16000 B
判题程序
Standard
作者
CHEN, Yue
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 (< 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 2
23 10
-2Sample Output:
Yes
Yes
No#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <algorithm>
#include <math.h>
#include <stdio.h>
#include <queue>
using namespace std;
int n,d;
int bin[105];
bool judge(int x)
{
if(x==1||x==0) return false;
if(x==2) return true;
for(int i=2;i*i<=x;i++)
{
if(x%i==0)
return false;
}
return true;
}
void fun(int x,int d)
{
int cnt=0;
while(x>=d)
{
bin[cnt++]=x%d;
x/=d;
}
if(x>0)
bin[cnt++]=x;
int num=0;
for(int i=0;i<cnt;i++)
{
num*=d;
num+=bin[i];
}
if(!judge(num))
printf("No\n");
else
printf("Yes\n");
}
int main()
{
while(scanf("%d",&n)!=EOF)
{
if(n<0)
break;
scanf("%d",&d);
if(!judge(n))
{
printf("No\n");
continue;
}
fun(n,d);
}
return 0;
}本文参与 腾讯云自媒体分享计划，分享自作者个人站点/博客。
原始发表：2016-05-30 ，如有侵权请联系 cloudcommunity@tencent.com 删除
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