阶乘

#include <iostream>
#include <cstring>
#include <algorithm>
#include <string>
using namespace std;
struct bign{
    int d[3000];
    int len;
    bign(){
        memset(d, 0, sizeof(d));
        len = 0;
    }
};
//输入大整数，以字符串读入，然后再把字符串另存为至bign结构体
bign change(string s){
    bign a;
    a.len = s.length();
    for(int i = 0; i < a.len; i++){
        a.d[i] = s[a.len - i - 1] - '0';
    }
    return a;
}
//高精度加法
bign add(bign a, bign b){
    bign c;
    int carry = 0;
    for(int i = 0; i < a.len || i < b.len; i++){
        int tmp = a.d[i] + b.d[i] + carry;
        carry = tmp / 10;
        c.d[c.len++] = tmp % 10;
    }
    if(carry != 0){
        c.d[c.len++] = carry;
    }
    return c;
}
//高精度阶乘
bign fac(int n){
    bign c;
    c.d[0] = 1;

    int j;
    int carry = 0;
    int point = 1;

    for(int i = 2; i <= n; i++){
        for(j = 0; j < point; j++){
            int tmp = i * c.d[j] + carry;
            carry = tmp / 10;
            c.d[j] = tmp % 10;
        }
        while(carry != 0){
            c.d[j] = carry % 10;
            carry /= 10;
            j++;
        }
        point = j;
    }

    c.len = point;
    return c;
}
void print(bign a){
    for(int i = a.len - 1; i >= 0; i--){
        printf("%d", a.d[i]);
    }
}
int main(){
    int n;
    bign y1, y2;
    y1.len = 1, y2.len = 1;
    scanf("%d", &n);
    for(int i = 1; i <= n; i++){
        //为奇数
        if(i & 1){
            y1 = add(y1, fac(i));
        }else{
            y2 = add(y2, fac(i));
        }
    }
    print(y1);
    printf(" ");
    print(y2);
    printf("\n");
    return 0;
}