Last Non Zero Digit of Factorial

Last Non Zero Digit of Factorial.cpp

#include <bits/stdc++.h>

#define MEM(a,b) memset((a),(b),sizeof(a))
#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIn(a,b) ((a)<(b)?(a):(b))
#define MIn4(a,b,c,d) MIn(MIn(MIn(a,b),c),d)
#define In freopen("In.txt", "r", stdin);
#define Out freopen("out.txt", "w", stdout);

#define i64 long long
#define u64 long long unsigned

#define sz 1000000

using namespace std;

int PTwo(int N)
{
    int T[]= {6,2,4,8};
    if(N==0) return 1;
    return T[N%4];
}
int LastNZDigit(int N)
{
    int A[]= {1,1,2,6,4};
    if(N<5) return A[N];
    return (PTwo(N/5)*LastNZDigit(N/5)*LastNZDigit(N%5))%10;
}

int main()
{
    int n;
    while(cin >> n)
        cout << LastNZDigit(n) << endl;
    return 0;
}