From d9d37754fd80c9f70123dfb4fd0ff9fb8af96971 Mon Sep 17 00:00:00 2001
From: Tim Stallard <code@timstallard.me.uk>
Date: Tue, 13 Dec 2016 23:09:07 +0000
Subject: [PATCH] Added day 13 part 2

---
 day13/part2.js | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 day13/part2.js

diff --git a/day13/part2.js b/day13/part2.js
new file mode 100644
index 0000000..36ad83d
--- /dev/null
+++ b/day13/part2.js
@@ -0,0 +1,43 @@
+var input = 1352;
+
+toBin = (number)=>(Number(number).toString(2).split("").map((a)=>(parseInt(a))));
+evenSum = (parts)=>(parts.reduce((a, b)=>(a+b))%2 == 0);
+checkCoord = (x, y)=>(evenSum(toBin(((x*x + 3*x + 2*x*y + y + y*y) + input))));
+
+var previous = [];
+
+function getNextCoords(x, y){
+  var next = [];
+  if(x > 0){
+    if(checkCoord(x-1, y)){
+      next.push([x-1, y]);
+    }
+  }
+  if(y > 0){
+    if(checkCoord(x, y-1)){
+      next.push([x, y-1]);
+    }
+  }
+  if(checkCoord(x+1, y)){
+    next.push([x+1, y]);
+  }
+  if(checkCoord(x, y+1)){
+    next.push([x, y+1]);
+  }
+  next = next.filter((pair)=>(previous.indexOf(pair.join(",")) == -1));
+  next.forEach((pair)=>{previous.push(pair.join(","))});
+  return next;
+}
+
+var coords = [[1,1]];
+
+function getNextAllCoords(){
+  return coords.map((pair)=>(getNextCoords(pair[0], pair[1]))).reduce((a, b)=>(a.concat(b)), []);
+}
+
+var i = 0;
+while(i < 50){
+  coords = getNextAllCoords();
+  i++;
+}
+console.log("Locations visited: ", previous.length);