Project Euler 19

Project Euler 19

by gurkavcu

JavaScript

function isLeapYear(year) { 
    
   if(year % 4 != 0 )
       return false;
    
   if(year % 400 == 0 )
       return true;

   if(year % 100 == 0 )
       return false;  

   if(year % 4 == 0 )
       return true;    
         
}

var months = [ 31 , 28 , 31 , 30 , 31 , 30 , 31 , 31 , 30 , 31 , 30 , 31 ];
var reference = 6 ;
var totalMonday = 0;

    for(var i=1901;i<2001;i++) {
 
        if(isLeapYear(i)) {
            months[1]=29;
        }
        else {
            months[1]=28;
        }
        
        for(var j = 0;j<12;j++){ 
            if(reference == 1 )
                totalMonday++;
           reference = 7 - ((months[j] - reference) % 7)
        }
    }

console.log(totalMonday);