抽象代码

#include <iostream>
#include <cstdio>
using namespace std;
long long a, b, c, d, e, f, g, h, A, B, C, D, E, F, G, H;
const long long jinwei = 1e9;
int main(){
	int n;
	cin >> n;
	while(n){
		A = 0, B = 0, C = 0, D = 0, E = 0, F = 0, G = 0, H = 1;
		for(int X = 2; X <= n; X++){
			A *= X, B *= X, C *= X, D *= X, E *= X, F *= X, G *= X, H *= X;
			int x = H / jinwei;
			H %= jinwei;
			G += x;
			x = G / jinwei;
			G %= jinwei;
			F += x;
			x = F / jinwei;
			F %= jinwei;
			E += x;
			x = E / jinwei;
			E %= jinwei;
			D += x;
			
			x = D / jinwei;
			D %= jinwei;
			C += x;
			x = C / jinwei;
			C %= jinwei;
			B += x;
			x = B / jinwei;
			B %= jinwei;
			A += x;
			//cout << A << endl;
		}
		a += A, b += B, c += C, d += D, e += E, f += F, g += G, h += H;
		int x = h / jinwei;
		h %= jinwei;
		g += x;
		x = g / jinwei;
		g %= jinwei;
		f += x;
		x = f / jinwei;
		f %= jinwei;
		e += x;
        x = e / jinwei;
        e %= jinwei;
        d += x;
		x = d / jinwei;
		d %= jinwei;
		c += x;
		x = c / jinwei;
		c %= jinwei;
		b += x;
		x = b / jinwei;
		b %= jinwei;
		a += x;
		n--;
	}
	if(a){
		cout << a;
		printf("%09d%09d%09d%09d%09d%09d%09d", b, c, d, e, f, g, h);
		return 0;
	}if(b){
		cout << b;
        printf("%09d%09d%09d%09d%09d%09d", c, d, e, f, g, h);
		return 0;
	}
	if(c){
		cout << c;
        printf("%09d%09d%09d%09d%09d", d, e, f, g, h);
		return 0;
	}if(d){
		cout << d;
		printf("%09d%09d%09d%09d", e, f, g, h);
		return 0;
	}if(e){
		cout << e;
        printf("%09d%09d%09d", f, g, h);
		return 0;
	}if(f){
		cout << f;
		printf("%09d%09d", g, h);
		return 0;
	}if(g){
        cout << g;
		printf("%09d", h);
		return 0;
	}cout << h;

	return 0;
}