HDUOJ 1042 N!

N!

Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 56209    Accepted Submission(s): 15948

Problem Description

Given an integer N(0 ≤ N ≤ 10000), your task is to calculate N!

 

Input

One N in one line, process to the end of file.

 

Output

For each N, output N! in one line.

 

Sample Input

1
2
3

 

Sample Output

1
2
6

 

#include <iostream>
#include <cstdio>
#include <cstring>
#define N 50000
using namespace std;

int fac[N];
int calc(int n)
{
    memset(fac,0,sizeof(fac));
    fac[0] = 1;
    for(int i=1; i<=n; i++)
    {
        for(int j=0; j<N; j++)
            fac[j] *= i;
        for(int j=0; j<N-1; j++)
        {
            if(fac[j]>=10)
            {
                fac[j+1] += fac[j]/10;
                fac[j] = fac[j]%10;
            }
        }
    }
    for(int i=N-1; i>=0;i--)
    {
        if(fac[i]!=0)
            return i;
    }
}

int main()
{
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        int i;
        i = calc(n);
        while(i>=0)
        {
            printf("%d",fac[i]);
            i--;
        }

        printf("\n");
    }
    return 0;
}