T02 Day of Week 给日期来求是周几

将字符串与数字对应起来用map<string,int>

似乎cin比scanf更合适一些，scanf老是报错或者输入不进去

先求出距0000-01-01的时长，这一天是周一，然后对7取余

#include<iostream>
#include<vector>
#include<map>
using namespace std;
#define run(x) (x%400==0||(x%4==0&&x%100!=0)?1:0)


typedef struct date{
    int y,m,d;
}date;
const int yd[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}};




int days(date a){       //求出距0000-01-01的时长
    int y=a.y,m=a.m,d=a.d,sum=0;
    for (int i = 1; i < y; ++i)
    {
        if (run(i))
        {
            sum+=366;
        }
        else
        {
            sum+=365;
        }
    }
    for(int i=1; i<m; i++)
    {
        sum+=yd[run(y)][i];
    }
    sum+=d;
    return sum;
}
int main(void){

    vector<string> days_of_week = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

    map<string, int> months;
    months["January"] = 1;
    months["February"] = 2;
    months["March"] = 3;
    months["April"] = 4;
    months["May"] = 5;
    months["June"] = 6;
    months["July"] = 7;
    months["August"] = 8;
    months["Semptember"] = 9;
    months["October"] = 10;
    months["November"] = 11;
    months["December"] = 12;

    string month;
    date a,b;
    int sum=0;
    while (cin>>a.d>>month>>a.y){
        a.m=months[month];

        sum = days(a);
        cout<<days_of_week[sum%7]<<endl;
    }

}