HackerEarth Small Factorials problem solution

In this HackerEarth Small Factorials problem solution, You are asked to calculate factorials of some small positive integers.

HackerEarth Small Factorials problem solution.

#include<bits/stdc++.h>

 

#define ll long long
#define ull unsigned long long
#define repA(i,a,n) for(int i=a;i<n;i++)
#define repD(i,a,n) for(int i=n-1;i>=a;i--)

#define fast ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)

 

using namespace std;
#define MAX 500
int res[MAX];

int multiply(int x, int res[], int res_size);

void factorial(int n)

{

   res[0] = 1;

   int res_size = 1;
    for (int x=2; x<=n; x++)

   {

       res_size = multiply(x, res, res_size);

   }

   

   for (int i=res_size-1; i>=0; i--)

       cout << res[i];

}

 

int multiply(int x, int res[], int res_size)

{

   int carry = 0;

 

   for (int i=0; i<res_size; i++)

   {

       int prod = res[i] * x + carry;

       res[i] = prod % 10;  

       carry  = prod/10;    

   }

 

   while (carry)

   {

       res[res_size] = carry%10;

       carry = carry/10;

       res_size++;

   }

   return res_size;

}

 

int main(){

  fast;

  int t;
 cin>>t;
 while(t--){

     

     int n;
     cin>>n;
     factorial(n);
     cout<<"\n";

 }

}