USACO problem

friday.cpp

#include<bits/stdc++.h>
using namespace std;

string convert(int n) {
    string arr[]={"mon","tue","wed","thur","fri","sat","sun"};
    return arr[n%7];
}

string mon_convert(int n){
    string arr[]={"jan","feb","mar","april","may","june","july","aug","sep","oct","nov","dec"};
    return arr[n%12];
}

int main(){
    int day[7] = {};
    int n; cin >> n; n = 20;
    for (int y=1900; y<1900+n; y++) {
        bool isLeapYear = ((y%10 == 0 && (y/10)%10 == 0)) ? (y%400==0) : (y%4==0);
        int dayCode = 0;
        for (int i=0; i<12; i++) {
            dayCode += 12;
            //cout<<mon_convert(i)<<" convert("<<dayCode<<" % 7 = "<<(dayCode%7)<<") = "<<convert(dayCode)<<endl;
            day[dayCode % 7]++; // increment frequency
            // go to first day of next month
            if (i == 1) {
                int numDays = isLeapYear ? 28 : 27;
                dayCode += (numDays - 12);
            }
            else if (i == 3 || i == 5 || i == 8 || i == 10) {
                dayCode += 18;
            } else {
                dayCode += 19;
            }
        }
    }
    for (int i=0; i<7; i++) {
        cout << day[i] << " ";
    }
}

/*
mon=1
tue=3
wed=1
thur=2
fri=2
sat=2
sun=1
*/