Add 337_House_Robber_III.java

Author: Sean Prashad

Dynamic Programming/337_House_Robber_III.java

@@ -0,0 +1,28 @@
+class Solution {
+    public int rob(TreeNode root) {
+        return helper(root, new HashMap<TreeNode, Integer>());
+    }
+
+    private int helper(TreeNode root, Map<TreeNode, Integer> m) {
+        if (root == null) {
+            return 0;
+        }
+        if (m.containsKey(root)) {
+            return m.get(root);
+        }
+
+        int result = 0;
+
+        if (root.left != null) {
+            result += helper(root.left.left, m) + helper(root.left.right, m);
+        }
+
+        if (root.right != null) {
+            result += helper(root.right.left, m) + helper(root.right.right, m);
+        }
+
+        result = Math.max(result + root.val, helper(root.left, m) + helper(root.right, m));
+        m.put(root, result);
+        return result;
+    }
+}