题解 | #Day of Week#

#include <cstdio>
#include <iostream>
#include<string>
#include<map>
using namespace std;
//这题真的挺费事的
//我自己随便找了一个久远的星期一的一天，然后计算两个日期之间的天数差即可
int solve(int year, int month, int day, int year2, int month2, int day2) {
    int data[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    if ((year % 100 != 0 && year % 4 == 0) || year % 400 == 0) data[2] = 29;
    int res = 0;
    int i = 0;
    res -= day;
    while (year != year2) {
        for (i = month; i <= 12; i++) {
            res += data[i];
        }
        if (year != year2) {
            month = 1;
            year += 1;
            //在改变年份的时候记得修改2月的日期！！！！！
            if ((year % 100 != 0 && year % 4 == 0) ||
                    year % 400 == 0)          data[2] = 29;
            else data[2] = 28;
        }

    }
    if (year == year2) {

        while (month < month2) {
            res += data[month];
            month++;
        }
        res += (day2 + 1);

    }
    return res;


    // printf("%d-%02d-%02d\n", year, i, addDay);

}

int main() {
    int num1, num2;
    map<string, int> m;
    map<int, string> week;

    m["January"] = 1;
    m["February"] = 2;
    m["March"] = 3;
    m["April"] = 4;
    m["May"] = 5;
    m["June"] = 6;
    m["July"] = 7;
    m["August"] = 8;
    m["September"] = 9;
    m["October"] = 10;
    m["November"] = 11;
    m["December"] = 12;
    week[1] = "Monday";
    week[2] = "Tuesday";
    week[3] = "Wednesday";
    week[4] = "Thursday";
    week[5] = "Friday";
    week[6] = "Saturday";
    week[0] = "Sunday";//星期天尤其记得是0序号
    int day, year;
    string month;
    while (cin >> day >> month >> year) {
        int m1 = m[month];
        int days = solve( 1969, 12, 29, year, m1, day);
        days %= 7;
        cout << week[days] << endl;

    }


}
// 64 位输出请用 printf("%lld")