hdu1042 N!

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1042

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

1

2

3

 

 

Sample Output

1

2

6

 

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 ("\n");

34     }

35     return 0;

36 }