题解 | #日期累加#

#include <iostream>
#include<iomanip>
using namespace std;
int Month[13] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };
void LastDay(int year, int month, int day, int num)
{
    if (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0))
    {
        Month[2] = 29;
    }
    else
    {
        Month[2] = 28;
    }
    int m = 0;
    if (day + num <= Month[month])
    {
        day += num;
        cout << year << "-" << setfill('0') << setw(2) << month << "-" << setfill('0') << setw(2) << day << endl;

        return;
    }
    num -= Month[month] - day;
    if (month == 12)
    {
        month = 0;
        year++;
        if (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0))
        {
            Month[2] = 29;
        }
        else
        {
            Month[2] = 28;
        }
    }
    int i = 0;
last:
    for (i = month + 1; num > Month[i] && i != 13; i++)
    {
        num -= Month[i];
    }
    month = i;
    if (i == 13 && num <= 0)
    {
        month = 12;
        day = Month[month] - num;
        cout << year << "-" << setfill('0') << setw(2) << month << "-" << setfill('0') << setw(2) << day << endl;
        return;
    }
    else if (i == 13 && num > 0)
    {
        ++year;
        month = 0;
        if (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0))
        {
            Month[2] = 29;
        }
        else
        {
            Month[2] = 28;
        }
        goto last;
    }
    day = num;
    cout << year << "-" << setfill('0') << setw(2) << month << "-" << setfill('0') << setw(2) << day << endl;


}
int main()
{
    int n = 0, year, month, day, num;
    cin >> n;
    for (int i = 0; i < n; i++)
    {
        cin >> year >> month >> day >> num;
        LastDay(year, month, day, num);
    }
}