poj--2649 factovisors

Description
The factorial function, n! is defined thus for n a non-negative integer:
0! = 1

n! = n * (n-1)! (n > 0)

We say that a divides b if there exists an integer k such that
k*a = b

Input
The input to your program consists of several lines, each containing two non-negative integers, n and m, both less than 2^31.
Output
For each input line, output a line stating whether or not m divides n!, in the format shown below.
Sample Input
6 9
6 27
20 10000
20 100000
1000 1009
Sample Output
9 divides 6!
27 does not divide 6!
10000 divides 20!
100000 does not divide 20!
1009 does not divide 1000!

---

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

#define N 100000
int prime[N],vis[N],num;

void eular()
{
    num = 0;
    memset(vis, 1, sizeof(vis));
    vis[0] = vis[1] = 0;

    for (int i=2; i<N; i++)
    {
        if (vis[i])
        {
            prime[num++] = i;
        }

        for (int j=0; j<num && i*prime[j] < N; j++)
        {
           vis[i * prime[j]]= 0;

           if (i%prime[j] == 0)
           {
              break;
           }
        }
    }
}

int coun(int a,int b)
{
    int y = 0;
    while (a)
    {
        a /= b;
        y += a;
    }
    return y;
}

int flag(int n,int m)
{
     for (int i=0; i<num && prime[i]<=sqrt(m); i++)
       {

           if (m % prime[i] == 0)
           {
                int x = 0;

                while (m % prime[i] == 0)
               {
                  m = m/prime[i];
                  x++;
               }

             if (x > coun(n,prime[i]))
             {
               return 0;
             }
          }
    }

    if (m > 1 &&  n < m)
    {
        return 0;
    }
    else
    {
        return 1;
    }
}

int main()
{

   int n,m;

   eular();

   while (scanf ("%d%d",&n,&m) != EOF)
   {
       if (m==0)
       {
           printf ("%d does not divide %d!\n",m,n);
           continue;
       }
       int mm =m,nn = n;

       if (flag(n,m) == 0)
       {
           printf ("%d does not divide %d!\n",mm,nn);
       }
       else
       {
           printf ("%d divides %d!\n",mm,nn);
           //continue;
       }

   }
    return 0;
}