题解 | #日期类#(大刀砍蚂蚁)

#include <iostream>
using namespace std;

int daytab[2][13]={
    {0,31,28,31,30,31,30,31,31,30,31,30,31},
    {0,31,29,31,30,31,30,31,31,30,31,30,31}
};

//日期类
class Date{
private:
    int year,month,day;
public:
    Date(int y,int m,int d):year(y),month(m),day(d){};

    bool isLeapYear(int year){
        return year%100!=0 && year%4==0 || year%400==0;
    }
	//日期转化为这一年的第几天
    int date2day(int year,int month,int day){
        int row = isLeapYear(year);
        int res = 0;
        for(int i=1;i<month;i++){
            res += daytab[row][i];
        }
        return res+day;
    }
	//天数转化为日期
    void day2date(int &year,int &month,int &day){
        int row = isLeapYear(year);
        for(month=1;day>daytab[row][month];month++){
            day-=daytab[row][month];
        }
    }

  //得出下一年
    void nextDate(int &year,int &month,int &day){
        int nextday = date2day(year,month,day)+1;
        if(nextday>365 + isLeapYear(year)){
            year++;
            month = 1;
            day = 1;
        }else{
            day = nextday;
            day2date(year,month,day);
        }
    }

  //打印下一年
    void printNextDate(int year,int month,int day){
        nextDate(year,month,day);
        printf("%04d-%02d-%02d\n",year,month,day);
    }

    
};

int main() {
    int num;
    cin>>num;
    
    int year,month,day;
    while(cin>>year>>month>>day){
        Date date(year,month,day);
        date.printNextDate(year,month,day);
    }
}