万位制，先计算10000！的位数，然后考虑分配多大的数组！
Accepted 1984MS 240K
1 # include <stdio.h>
2 # include <memory.h>
3
4 # define N 8200
5 # define BASE 100000
6
7 int main()
8 {
9 int n, i, j;
10 long long c, tmp;
11 int a[N];
12
13 freopen("in.txt", "r", stdin);
14 freopen("out.txt", "w", stdout);
15
16 while (~scanf("%d", &n))
17 {
18 memset(a, 0, sizeof(a));
19 a[0] = 1;
20 for (i = 1; i <= n; ++i)
21 {
22 for (c=0, j=0; j < N; ++j)
23 {
24 tmp = a[j]*i + c;
25 c = tmp / BASE;
26 a[j] = tmp - c*BASE;
27 }
28 }
29 j = N-1;
30 while (!a[j]) --j;
31 printf("%d", a[j--]);
32 while (j >= 0)
33 printf("%05d", a[j--]);
34 printf("\n");
35 }
36
37 return 0;
38 }