hdu 1042 大数阶乘 ,

hdu 1042 大数阶乘, 　原题链接,　click here.

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

Author

JGShining（极光炫影）

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对此,我只想说,0的阶乘是1之前我怎么不知道… … 特判的我傻傻地交了一发又一发…去了特判之后,就A了,都是泪…

#include<bits/stdc++.h>
using namespace std;
const int maxn = 36000;
//10000  的阶乘有  35661位;
int f[maxn];
int main()
{
int a;
while(~scanf("%d",&a))
{
f[0]=1;
int c,len=1,j;
//len直接记录位数,不用再从后往前遍历了;
for(int i=1;i<=a;i++)
{
c=0;
for( j=0;j<len;j++)
{
f[j]=f[j]*i+c;
c=f[j]/10;
f[j]%=10;
}
while(c)//加上多余的没加上的c;
{
f[len++]=c%10;
c/=10;
}
}
//长度为 len,从len-1开始输出;
for(int i=len-1;i>=0;i--)
printf("%d",f[i]);
printf("\n");
}
return 0;
}