N！ (数组）

 1 #include <iostream>
 2 using namespace std;
 3 const int MAXN = 3000;
 4 int f[MAXN];
 5 
 6 int main(){
 7     int n;
 8     cin >> n;
 9     f[0] = 1;
10     int i, j;
11     for(i = 2; i <= n; i++){
12         int c = 0;
13         for(j = 0; j < MAXN; j++){
14             int s = f[j] * i + c;
15             c = s / 10;
16             f[j] = s % 10;
17         }
18     }
19     for(j = MAXN - 1; j >= 0; j--){
20         if(f[j]) break;
21     }
22     for(i = j; i >= 0; i--)
23         cout << f[i];
24     cout << endl;
25     return 0;
26 }