HDU 杭电OJ 1042 N！

#include "bits/stdc++.h"
#define max_n 10005
using namespace std;

int a[max_n + 10];

int main(){
int n;
while (scanf("%d", &n) != EOF){
memset(a,0,sizeof(a));
a[0] = 1;
int count = 2;
while (count <= n){
for (int i = 0; i <= max_n; i++){
a[i] *= count;
}

for (int i = 0; i <= max_n; i++){
if (a[i] > 10000) {
a[i+1] += a[i] / 10000;
a[i] = a[i] % 10000;
}
}
count++;
}
int p = max_n + 9;
while (a[p] == 0 && p > 0){
p--;
}

printf("%d",a[p]);

for (int i = p - 1; i >= 0; i--){
printf("%04d",a[i]);
}
cout << endl;
}
}