OJ-Problems-Source/QUSTOJ/1734.c

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2016-05-21 12:40:11 +08:00
#include <stdio.h>
//Written by Coffee. 判断素数
int isPrime(int num)
{
if (num == 2 || num == 3)
{
return 1;
}
if (num % 6 != 1 && num % 6 != 5)
{
return 0;
}
for (int i = 5; i*i <= num; i += 6)
{
if (num % i == 0 || num % (i+2) == 0)
{
return 0;
}
}
return 1;
}
int main()
{
int a;
scanf("%d",&a);
for(int i=2;i<=a/2;i++)
{
if(isPrime(i)&&isPrime(a-i))
{
printf("%d=%d+%d\n",a,i,a-i);
}
}
return 0;
}