AOC.2017.JS

// Day 3 Part 1
console.log((function (input) {
  let [x,y]=[0,0];
  let [inc,dir,mem]=[1,1,1];
  for (;;) {
	for (let i=1;i<inc+1;i++) {
	  mem++;
	  x = (dir===1) ? x+1 : (dir===3) ? x-1 : x;
	  y = (dir===2) ? y+1 : (dir===4) ? y-1 : y;
	  if (mem===input) return Math.abs(x) + Math.abs(y)
	}
	dir = (dir===4) ? 1 : dir+1;
	if ((dir===1) || (dir===3)) inc++;
  }
})(368078));

// Day 3 Part 2
console.log((function (input) {
  let [x,y]=[0,0];
  let [inc,dir]=[1,1];
  let memory = {"0,0":1};
  let g = function(x,y) { return memory[x+","+y] || 0};
  for (;;) {
	for (let i=1;i<inc+1;i++) {
	  x = (dir===1) ? x+1 : (dir===3) ? x-1 : x;
	  y = (dir===2) ? y+1 : (dir===4) ? y-1 : y;
	  memory[x+","+y]=g(x+1,y-1)+g(x+1,y)+g(x+1,y+1)+g(x-1,y-1)+g(x-1,y)+g(x-1,y+1)+g(x,y-1)+g(x,y+1);
	  if (memory[x+","+y]>input) return memory[x+","+y];
	}
	dir = (dir===4) ? 1 : dir+1;
	if ((dir===1) || (dir===3)) inc++;
  }
})(368078));