Project Euler 15 Starting in the top left corner of a 22 grid, and only being able to move to the right and down, there are exactly 6 routes to the bottom right corner.

ProjectEuler_Problem15.js

http://projecteuler.net/problem=15

var memory;

var f = function(x,y){
    var a=0,b=0;
    console.log ( 'x:'+x+ ' y:'+y );
    
    if (memory[x][y] !=0){
     	return memory[x][y];
    }
    
    if(x===0 && y===0) {
    	return 0;
    }
	
	if (x===0 || y===0 ) {
	   return memory[x][y]=1;
    }
	memory[x][y]= f(x-1,y)+f(x,y-1);
	return memory[x][y];
}


var start=function(){
	memory=new Array(21);
	for(i=0;i<21;i++){
		memory[i]=new Array(21);
		for(j=0;j<21;j++){
			memory[i][j]=0;
		}
	}

	var result=0;
	result=f(20,20);
	console.log(result);
}();