质数

判断是否是素数

#include <stdio.h>
#include <stdlib.h>

int isPrime(unsigned int n)
{
	unsigned int i=0;
	if(n == 1) return -1;
	if(n == 2) return 1;
	if(n%2 == 0) return -1;
	if(n == 3) return 1;
	if(n%3 == 0) return -1;
	for(i=5;i*i<=n;i=i+2)
	{
		if(n%i == 0)
			return -1;
	}
	return 1;
}


int main()
{
	unsigned int n;
	scanf("%u", &n);	
	if(isPrime(n)==1)
		printf("YES");
	else
		printf("NO");
}