# House Robber III

## Problem

The thief has found himself a new place for his thievery again. There is only one entrance to this area, called the "root." Besides the root, each house has one and only one parent house. After a tour, the smart thief realized that "all houses in this place forms a binary tree". It will automatically contact the police if two directly-linked houses were broken into on the same night. Determine the maximum amount of money the thief can rob tonight without alerting the police.

## Example

  3
/ \
2   3
\   \
3   1

Maximum amount of money the thief can rob = 3 + 3 + 1 = 7.

    3
/ \
4   5
/ \   \
1   3   1

Maximum amount of money the thief can rob = 4 + 5 = 9.

## Code - Java

/**
* Definition of TreeNode:
* public class TreeNode {
*   public int val;
*   public TreeNode left, right;
*   public TreeNode(int x) { val = x; }
* }
*/
public class Solution {
/**
* @param root: The root of binary tree.
* @return: The maximum amount of money you can rob tonight
*/
public int houseRobber3(TreeNode root) {
int[] dp = search(root);
return Math.max(dp, dp);
}

private int[] search(TreeNode root) {
int[] dp = new int;
if (root == null) {
return dp;
}
int[] left = search(root.left);
int[] right = search(root.right);

dp = Math.max(left, left) + Math.max(right, right);
dp = left + right + root.val;

return dp;
}
}