#include<bits/stdc++.h>
using namespace std;

// 判断是否为闰年
bool run_nian(int year) {
	return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0;
}

// 计算某年某月的天数
int TIANSHU(int year, int month) {
	static int days[] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
	if (month == 2 && run_nian(year))
		return 29;

	return days[month];
}

// 计算指定日期是星期几（蔡勒公式）
int WEEK(int year, int month, int day) {
	int week;
	if (month < 3) {
		month += 12;
		year--;
	}
	int c = year / 100;
	int y = year % 100;
	if ((year < 1582) || (year == 1582 && month <= 10 && day <= 4))
		week = (day + 1 + 2 * month + 3 * (month + 1) / 5 + year + year / 4 + 5) % 7;
	else if ((year > 1582) || (year == 1582 && month >= 10 && day >= 10))
		week = (c / 4 - 2 * c + y + y / 4 + 13 * (month + 1) / 5 + day - 1) % 7;
	else
		week = 8;
	if (week < 0)
		week += 7;
	return week;
}

// 打印单月日历
void danlie(int year, int month) {
	if (year != 1582) {
		cout << "    " << year << "年" << month << "月\n";
		cout << " 一 二 三 四 五 六 日\n";

		int weekday = WEEK(year, month, 1);
		for (int i = 0; i < weekday % 7; i++)
			cout << "   ";

		int days = TIANSHU(year, month);
		for (int i = 1; i <= days; ++i) {
			cout << setw(3) << i;
			if ((weekday + i) % 7 == 0)
				cout << "\n";
		}
		cout << "\n";
	} else {
		if (month != 10) {
			cout << "    " << year << "年" << month << "月\n";
			cout << " 一 二 三 四 五 六 日\n";

			int weekday = WEEK(year, month, 1);
			for (int i = 0; i < weekday % 7; i++)
				cout << "   ";

			int days = TIANSHU(year, month);
			for (int i = 1; i <= days; ++i) {
				cout << setw(3) << i;
				if ((weekday + i) % 7 == 0)
					cout << "\n";
			}
			cout << "\n";
		}

		else {
			cout << "    " << year << "年" << month << "月\n";
			cout << " 一 二 三 四 五 六 日\n";

			int weekday = WEEK(year, month, 1);
			for (int i = 0; i < weekday % 7; i++)
				cout << "   ";

			int days = TIANSHU(year, month);
			for (int i = 1; i <= days; ++i) {
				if (i <= 4 || i > 14)
					cout << setw(3) << i;
				else
					continue;
				if (i == 16 || i == 23 || i == 30)
					cout << "\n";
			}
			cout << "\n";
		}
	}
}






// 打印双月日历（并排显示两个月）
void shuang_yueli(int year, int month) {
	int days1 = TIANSHU(year, month);
	int days2 = TIANSHU(year, month + 1);

	cout << "    " << year << "年" << month << "月 - " << year << "年" << month + 1 << "月\n";
	cout << " 一 二 三 四 五 六 日      一 二 三 四 五 六 日\n";

	int weekday1 = WEEK(year, month, 1);
	int weekday2 = WEEK(year, month + 1, 1);
	int i, j, ij1, ij2;
	for (int m = 0; m < weekday1; ++m)
				cout << "    ";
	for (i = 1; i < days1; i++) {
		for (j = 1; j < days2; j++) {
			for (ij1 = 1; ij1 <= (weekday1 + i) % 7; ij1++) {
				cout << setw(3) << i;
				i++;
			}
			for (int m = 0; m < weekday2; ++m)
				cout << "    ";
			for (ij2 = 1; ij2 <= (weekday2 + j) % 7; ij2++) {
				cout << setw(3)<< j;
				j++;
				if((weekday2+j)%7==0)
				{
					cout<<"\n";
				}
			}
		}
	}
}

// 显示菜单并获取用户选择
int menu() {
	int choice;
	cout << "万年历程序菜单：\n";
	cout << "1. 查询某年某月某日是周几及该年是否为闰年\n";
	cout << "2. 输出指定年份的单月日历\n";
	cout << "3. 输出指定年份的双月日历\n";
	cout << "4. 退出程序\n";
	cout << "请输入你的选择：";
	while (scanf("%d", &choice) != 1) {
		while (getchar() != '\n') ;
		printf("无效的选择，请重新输入\n");
	}
	return choice;
}

// 获取有效年份输入
int wannianli() {
	int year;
	cout << "请输入年份（公元后）：";
	while (scanf("%d", &year) != 1) {
		while (getchar() != '\n') ;
		printf("无效的选择，请重新输入\n");
	}
	return year;
}

// 获取有效月份输入
int month_1() {
	int month;
	cout << "请输入月份（1 - 12）：";
	while (scanf("%d", &month) != 1) {
		while (getchar() != '\n') ;
		printf("无效的选择，请重新输入\n");
	}
	if (month > 12 || month < 1) {
		printf("无效的选择，请重新输入\n");
	}
	return month;
}

// 获取有效日期输入
int DAY(int year, int month) {
	int date;
	cout << "请输入日期（1 - " << TIANSHU(year, month) << "）：";
	while (scanf("%d", &date) != 1) {
		while (getchar() != '\n') ;
		printf("无效的选择，请重新输入\n");
	}
	return date;
}

int main() {
	int choice;
	do {
		choice = menu();

		switch (choice) {
			case 1: {
				int year = wannianli();
				int month = month_1();
				int date = DAY(year, month);

				bool leap = run_nian(year);
				int weekday = WEEK(year, month, date);
				if (weekday == 0)
					cout << year << "年" << month << "月" << date << "日是星期天。\n";
				if (weekday == 8)
					cout << year << "年" << month << "月" << date << "日不存在。\n";
				if (weekday < 8 && weekday > 0)
					cout << year << "年" << month << "月" << date << "日是星期" << weekday << "。\n";
				cout << year << (leap ? "是闰年。\n" : "不是闰年。\n");
				break;
			}
			case 2: {
				int year = wannianli();
				for (int month = 1; month <= 12; ++month) {
					danlie(year, month);
				}
				break;
			}
			case 3: {
				int year = wannianli();
				for (int month = 1; month < 12; month += 2) {
					shuang_yueli(year, month);
				}
				break;
			}
			case 4:
				cout << "程序已退出。\n";
				break;
			default:
				cout << "无效的选择，请重新输入。\n";
				break;
		}
	} while (choice != 4);

	return 0;
}