【洛谷P1009 阶乘之和】

前天刚写完N!,今天做这题就很简单了，秒天秒地秒空气O(∩_∩)O哈哈~

#include <iostream>
#include <algorithm> 
#include <string>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <set>
#include <map>
#include <vector>
#include <stack>
#include <queue>
#include <bitset> 
#include <unordered_map>
#include <unordered_set>
#define ll long long
#define vi vector<int> 
#define si set<int>
#define pi pair<int,int> 
#define pii pair<ll,ll> 
#define pb push_back
#define mp make_pair
#define lowbit(x) (x&(-x))
#define sci(x) scanf("%d",&(x))
#define scll(x) scanf("%lld",&(x))
#define sclf(x) scanf("%lf",&(x))
#define pri(x) printf("%d",(x))
#define rep(i,j,k) for(int i=j;i<=k;++i)
#define per(i,j,k) for(int i=j;i>=k;--i)
#define mem(a,b) memset(a,b,sizeof(a)) 
using namespace std;
int f[100][100]; 
int carry=0,digit=1;
int main()
{
	memset(f,0,sizeof(f));
	int N;
	cin>>N;
	for(int n=1;n<=N;n++){
			carry=0,digit=1;
			f[n][0]=1;
			for(int i=2;i<=n;i++){
	 		carry=0;
	 		for(int j=0;j<digit;j++){
	 			f[n][j] = f[n][j]*i+carry;
	 			carry = f[n][j]/10000;
	 			f[n][j]%=10000;
			 }
			 if(carry){
			 	f[n][digit++]=carry;
			 }
		 }
	}
 	for(int i=0;i<digit;i++){
 		carry=0;
 		for(int j=1;j<=N;j++){
 			f[0][i]+=f[j][i]+carry;
		 }
		 carry = f[0][i]/10000;
		 f[0][i]%=10000;
		 if(carry){
		 	f[0][i+1]=carry;
		 }
	 }
	 if(carry){
	 	f[0][digit++] = carry;
	 }
	 printf("%d",f[0][digit-1]);
	per(i,digit-2,0){
	 	printf("%04d",f[0][i]);
	 }
	 printf("\n");
   return 0;	
}