每日一九度之 题目1076：N的阶乘

//Asimple
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <vector>
#include <cctype>
#include <cstdlib>
#include <stack>
#include <cmath>
#include <set>
#include <map>
#include <string>
#include <queue>
#include <limits.h>
#define INF 0x7fffffff
using namespace std;
const int maxn = 3005;
typedef long long ll;
int n;
ll a[maxn];

int main(){
    while( ~scanf("%d",&n) ){
         if( n == 0 ){
             printf("1\n");
             continue;
         }
         //进位 
         int c = 0, len = 1;
         memset(a,0,sizeof(a));
         a[0] = 1;
         for(int i=1; i<=n; i++){
             c = 0;
             for(int j=0; j<len; j++){
                 a[j] = a[j] * i + c;
                 if( a[j]>=10 ){
                     c = a[j] / 10;
                     a[j] = a[j] % 10;
                 } else c = 0;
             }
             while( c != 0 ){
                 int t = c % 10;
                 a[len++] = t;
                 c = c / 10;
             }
         }
         int i, j;
         for(i=maxn; i>=0; i--){
             if( a[i] != 0 ){
                 break;
             }
         }
         for(j=i; j>=0; j--){
             printf("%d",a[j]);
         }
         printf("\n");
    } 
    return 0;
}