阶乘问题 n！后最右边非0的数

#include <cstdio>
#include <algorithm>
#define ll long long
#define maxn 800010
#define lson l,m,rt<<1
#define rson m+1,r,rt<< 1 | 1
using namespace std;
int s[100];
int main(){
    int num,n,add,pai[4]={6,2,4,8};
    while(~scanf("%d",&n)){
        num=n;
        add=0;
        while(num){
            if(num%5==2){
                add+=1;
            }
            else{
                if(num%5==4)
                    add+=2;
            }
            add+=num/5;
            num/=5;
        }
        if(n>1){
            printf("%d\n",pai[add%4]);
        }
        else printf("1\n");
    }
}