题解 | #Day of Week#

#include <iostream>
#include <string>
#include <map>
using namespace std;

int main() {
    int mday[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
    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}
    };
    string intToweekday[7] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};






    int year, mon,day;
    char str[100];
    string month;
    bool IsBefore;
    while (scanf("%d %s %d",&day,str,&year)!=EOF) { // 注意 while 处理多个 case
        month = str;
        mon = MonthToInt[month];
        if(year <2023 ||2023==year && mon<3 ||2023==year && 3==mon && day<8){
            IsBefore = true;
        }
        else{
            IsBefore=false;
        }

        int begY,begM,begD,endY,endM,endD;
        if(IsBefore){
            begY = year;
            begM = mon;
            begD = day;
            endY = 2023;
            endM = 3;
            endD = 8;
        }
        else{
            begY = 2023;
            begM = 3;
            begD = 8;
            endY = year;
            endM = mon;
            endD = day;
        }
        int totalDay=0;
        while(1){
            if(begY == endY && begM == endM && begD == endD)
            {
                break;
            }
            else{
                ++totalDay;
                bool isLeap = begY%400==0 || begY%4==0&&begY%100!=0;
                if(isLeap){
                    mday[2] = 29;
                }
                else{
                    mday[2] = 28;
                }
                ++begD;

                if(begD>mday[begM]){
                    begD = 1;
                    ++begM;
                    if(begM>12){
                        begM=1;
                        ++begY;
                    }
                }
            }
        }
        if(IsBefore){
            //今天周三 所以是3 (x+totalDay)%7 = 3;
            //x+totalDay = 7y+3
            //x = 7y+3 - totalDay;
            //(7y+3-totalDay)%7 = 
            printf("%s\n", intToweekday[(10-totalDay%7)%7].c_str());
        }
        else{
            printf("%s\n", intToweekday[(totalDay+3)%7].c_str());
        }
    }
}
// 64 位输出请用 printf("%lld")