POJ 1604

题意

求n！最后一位非零数字

思路

网上学习别人的代码后，截取n！的后五位避免超出int的范围

#include <iostream>
#include <cstring>
#include <cstdio>
#include <cmath>
using namespace std;

int s[10005];
int n;

void multiply(){
    int i,j;
    memset(s,0,sizeof(s));
    s[1] = 1;
    j = 1;
    for(i = 2;i <= 10000;i++){
        j *= i;
        while(j %10 == 0)
            j /= 10;

        j %= 10000;
        s[i] = j%10;

    }
}

int main()
{
    multiply();
    while(cin>>n){
        printf("%5d",n);
        cout<<" -> "<<s[n]<<endl;
    }
    return 0;
}