N! HDU 1042

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

123

 

 

Sample Output

126

 

 

思路：大数相乘，用数组来存放数字，存放的最大数字为9999，超过了就进位

#include <stdio.h>#define N 10000int main(){    long int a[10000]={0};    long int i,n,k=1,j;    for(i=1;i<N;i++)    {        a[i]=0;    }    a[0]=1;    while(scanf("%d",&n)!=EOF)    {        if(n==1)        {            printf("1");            printf("\n");            continue;        }        for(i=2;i<=n;i++)        {            for(j=0;j<k;j++)            {                a[j]*=i;            }            for(j=0;j<k;j++)            if(a[j]>N)            {                a[j+1]+=a[j]/N;                  a[j]%=N;            }            if(a[k]>0)                k++;        }        printf("%d",a[k-1]);        for(i=k-2;i>=0;i--)        {            printf("%04d",a[i]);        }        k=1;        for(i=1;i<N;i++)        {            a[i]=0;        }        a[0]=1;        printf("\n");    }    return 0;}