HDU 1042 N!

N!

Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others)
Total Submission(s): 83996    Accepted Submission(s): 24766

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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分析：一开始以为要用高精度，然后看了下 其他人的做法，原来可以直接用数组储存当前位

     然后又因为不知道 0!=1  WA了很多发..

     注意，一开始数组需要多长的话，可能需要试探性的取吧，再看ans[MAXN]是否为0

代码如下：

#include <cstdio>
#include <iostream>
#include <cstring>
#include <map>
#include <algorithm>
using namespace std;
typedef long long ll;
const int MAXN=40000;
int ans[MAXN];
int flag;
int main()
{
    int n,r,tmp;
while(scanf("%d",&n)!=EOF){
    flag=0;
     memset(ans,0,sizeof(ans));
     ans[0]=1;
     for(int i=2;i<=n;i++)
     {
         r=0;
        for(int j=0;j<=MAXN;j++)
        {
            tmp=ans[j]*i+r;
            ans[j]=tmp%10;
            r=tmp/10;

        }
     }
       for(int i=MAXN;i>=0;i--)
       {
          if(flag==0&&ans[i]==0)
          continue;
          else
          {
              flag=1;
              printf("%d",ans[i]);
          }
       }
       printf("
");
    }
    return 0;
}