Given an integer N, find its factorial.

Example 1:

Input: N = 5
Output: 120
Explanation : 5! = 1*2*3*4*5 = 120

Example 2:

Input: N = 10
Output: 3628800
Explanation :
10! = 1*2*3*4*5*6*7*8*9*10 = 3628800

Your Task:
You don't need to read input or print anything. Complete the function factorial() that takes integer N as input parameter and returns a list of integers denoting the digits that make up the factorial of N.

Expected Time Complexity : O(N)
Expected Auxilliary Space : O(1)

Constraints:
1 ≤ N ≤ 1000