题解 | #素数回文#

#include <stdio.h>
#include <math.h>

long long change_hui(int num)
{
	long long sum = 0;
	int count = 0;
	int a = num;

	while (a)
	{
		a /= 10;
		count++;
	}

	a = num;
	a /= 10;

	while (a)
	{
		sum = sum * 10 + a % 10;
		a /= 10;
	}
	return sum + pow(10, count - 1) * num;
}

int main()
{
	int t = 0;
	scanf("%d", &t);
	long long ret = change_hui(t);
	int flag = 1;
	for (int i = 2; i <= sqrt(ret); i++)
	{
		if (ret % i == 0)
		{
			flag = 0;
		}
	}
	if(flag==1)
	printf("prime");
	else
	printf("noprime");
	return 0;
}