Create 337. House Robber III

Author: khushi3004

337. House Robber III

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+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+class Solution {
+    Map<TreeNode,Integer> map=new HashMap<>();
+    public int rob(TreeNode root) {
+        if(root==null){
+            return 0;
+        }
+        if(map.containsKey(root)){
+            return map.get(root);
+        }
+        
+        int sum=root.val;
+        
+        if(root.left!=null){
+            sum+=rob(root.left.left);
+            sum+=rob(root.left.right);
+        }
+        
+        if(root.right!=null){
+            sum+=rob(root.right.left);
+            sum+=rob(root.right.right);
+        }
+        
+        int next_sum=rob(root.left)+rob(root.right);
+        
+        int res=Math.max(sum,next_sum);
+        map.put(root,res);
+        return res;
+    }
+}