基姆拉尔森，输入年月日输出周几

先水一篇。。。。。微困

zzz。。。

#include <bits/stdc++.h>
using namespace std;
int CalcWeekDay(int year, int month, int day){
    if(month ==1 || month == 2){
        month+=12;
        year--;
    }
    int ret = ((day+2*month+3*(month+1)/5+year+year/4-year/100+year/400)+1)%7;
    return (0 == ret) ? 7 : ret;
}
int main()
{
    int a,b,c;
    cin>>a>>b>>c;
    cout<<CalcWeekDay(a,b,c);
}