1007 素数对猜想 (20)

1007 素数对猜想 (20)

---

链接：点我

---

思路同1013

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

bool isPrime(int val)
{
    if (val <= 1)
        return false;

    int sqr = (int) sqrt(1.0 * val);
    for (int j = 2; j <= sqr; j++)
    {
        if (val % j == 0)
            return false;
    }

    return true;
}


int main (void)
{
    int val = 0;
    int cout = 0;
    int i = 0;

    scanf ("%d", &val);

    for (i = 3; i +2 <= val; i += 2)
    {
        if ((isPrime(i) == true) && (isPrime(i+2) == true))
        {
            cout ++;    
        }   
    }   
    printf ("%d", cout);
}