Help me!!!

#include <iostream>
#include <cstring>

using namespace std;

int f[100010];

int main()
{
    int t;
    cin >> t;

    while (t -- )
    {
        int n, a;
        cin >> n >> a;

        memset(f, 0, sizeof f);
        f[1] = 1;
        int l = 1;
        for (int i = 2; i <= n; i ++ )
        {
            int w = 0;
            for (int j = 1; j <= l; j ++ )
            {
                f[j] = f[j] * i + w;
                w = f[j] / 10;
                f[j] %= 10;
            }
            l ++ ;
            while (w)
            {
                f[l] = w % 10;
                l ++ ;
                w /= 10;
            }
        }

        int sum = 0;

        for (int i = 1; i <= l; i ++ )
            if (f[i] == a)  sum ++ ;

        cout << sum << endl;
    }

    return 0;
}