2001年1月1日是星期六，给定一个整数n，判断n天后是哪年哪月哪天，星期几

# include<iostream>
using namespace std;

int month[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
int y = 2000;
int m = 1, d = 1, week = 6;
int n;

bool is_run(int x)
{
    if(x%4 == 0 && x%100!=0 || x%400 == 0) return true;
    return false;
}
int main()
{
    cin>>n;
    for(int i = 1; i<=n; i++)
    {
        week+=1;
        if(week>7) week = 1;
        d+=1;
        int tmp = month[m];
        if(is_run(y)&&m == 2) tmp+=1;
        if(d>tmp)
        {
            d = 1;
            m++;
            if(m>12)
            {
                m = 1;
                y++;
            }
        }
    }
    printf("%d/%d/%d %d\n",y,m,d,week);
}