题解 | #Day of Week#

//土尔逊Torson 编写于2023/3/31
#define _CRT_SECURE_NO_WARNINGS
#include <map>
#include <cstdio>
#include <string>
using namespace std;
int main() {
	int mday[13] = { -1,31,28,31,30,31,30,31,31,30,31,30,31 };
	string intToWeekday[8] = { "Sunday","Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };
	map<string, int> monthToint = {
		{"January",1},
		{"February",2},
		{"March",3},
		{"April",4},
		{"May",5},
		{"June",6},
		{"July",7},
		{"August",8},
		{"September",9},
		{"October",10},
		{"November",11},
		{"December",12}
	};
	int year, mon, day;
	char str[100];
	string month;
	bool isBefore;
	while (scanf("%d%s%d", &day, str, &year) != EOF) {
		month = str;
		mon = monthToint[month];
		if (year < 2023 || 2023 == year && mon < 3 || 2023 == year && 3 == mon && day < 19) {
			isBefore = true;
		}
		else {
			isBefore = false;
		}

		int begYear, begMon, begDay, endYear, endMon, endDay;
		if (isBefore) {
			begYear = year;
			begMon = mon;
			begDay = day;
			endYear = 2023;
			endMon = 3;
			endDay = 19;
		}
		else {
			begYear = 2023;
			begMon = 3;
			begDay = 19;
			endYear = year;
			endMon = mon;
			endDay = day;
		}
		int totalDay = 0;
		while (true) {
			if (begYear == endYear && begMon == endMon && begDay == endDay) {
				break;
			}
			++totalDay;
			bool isLeap = begYear % 400 == 0 || begYear % 4 == 0 && begYear % 100 != 0;
			if (isLeap) {
				mday[2] = 29;
			}
			else {
				mday[2] = 28;
			}
			++begDay;
			if (begDay > mday[begMon]) {
				begDay = 1;
				++begMon;
				if (begMon > 12) {
					begMon = 1;
					++begYear;
				}
			}
		}
		if (isBefore) {
			//(x + totalDay)%7=7; >== x = (14 - totalDay % 7) % 7;
			printf("%s\n", intToWeekday[(14 - totalDay % 7) % 7].c_str());
		}
		else {
			printf("%s\n", intToWeekday[(totalDay + 7) % 7].c_str());
		}
	}
	//system("pause");
	return EXIT_SUCCESS;
}