I finissshhheeeeedddd..

src/Day6.java

@@ -56,11 +56,45 @@ public static void main(String[] args) throws IOException {
                 if (hasAncestor(o, a)) orbits ++;
             }
         }
-        System.out.println(orbits);
+        System.out.println("Part 1: " + orbits);
+
+        String target = "SAN";
+        System.out.println("Part 2: " + calDis(tree.get("YOU"), tree.get("SAN")));
+
         double endTime = System.currentTimeMillis();
         System.out.println("Time: " + (endTime - startTime) + "ms");
     }
 
+    static int calDis(Node a, Node b){
+        // find first shared ancestor
+
+        List<Node> aParents = new ArrayList<Node>();
+        List<Node> bParents = new ArrayList<Node>();
+
+        Node curr = a.getParent();
+        for (int i = a.getHeight(); i > 0; i --){
+            aParents.add(curr);
+            curr = curr.getParent();
+        }
+
+        curr = b.getParent();
+        for (int i = b.getHeight(); i > 0; i --){
+            bParents.add(curr);
+            curr = curr.getParent();
+        }
+
+        List<Node> sharedParents = new ArrayList<Node>();
+        for (Node n : aParents){
+            if (bParents.contains(n)){
+                sharedParents.add(n);
+            }
+        }
+
+        Node common = sharedParents.get(0);
+        System.out.println("Common: " + common);
+        return (a.getHeight() - common.getHeight() + b.getHeight() - common.getHeight() - 2);
+    }
+
     static boolean hasAncestor(Node offspring, Node ancestor){
         Node next = offspring.getParent();
         for (int i = 0; i < offspring.getHeight() - ancestor.getHeight(); i++) {

test.txt

@@ -1,7 +1,13 @@
-B)D
-COM)A
-A)B
-A)C
+COM)B
+B)C
+C)D
 D)E
-E)G
-G)F
+E)F
+B)G
+G)H
+D)I
+E)J
+J)K
+K)L
+K)YOU
+I)SAN