N!

Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 58278 Accepted Submission(s): 16547

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

Sample Output

题目大意：求N! 比如求123!我们肯定是要1*2*3*.....*123；如果直接这样做下去，毋庸置疑的会超时，那么我们就要将他一位一位存下来。一位一位的乘过去。做过的东西，还要想好久，还是不扎实，一定要多动脑。

详见代码。

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 
 5 using namespace std;
 6 int num[80000];
 7 int main ()
 8 {
 9     int n,pre;
10     while (~scanf("%d",&n))
11     {
12         memset(num,0,sizeof(num));
13         num[0]=1;
14         int len=1;
15         for (int i=2; i<=n; i++)
16         {
17             pre=0;
18             for (int j=0; j<len; j++)
19             {
20                 num[j]=num[j]*i+pre/10;
21                 pre=num[j];
22                 num[j]=num[j]%10;
23             }
24             while (pre>9)
25             {
26                 num[len]=pre/10%10;
27                 len++;
28                 pre/=10;
29             }
30         }
31         for (int i=len-1; i>=0; i--)
32             printf ("%d",num[i]);
33         printf ("
");
34     }
35     return 0;
36 }