337. House Robbery III

337. House Robbery III

answer

​ Use depth-first search, divided into two cases of using the root node and not using the root node, recursively search the left and right child nodes.

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    
    
    public int rob(TreeNode root) {
    
    
        int[] result = dfs(root);
        return Math.max(result[0],result[1]);
    }
    public int[] dfs(TreeNode root){
    
    
        if(root == null){
    
    
            return new int[]{
    
    0,0};
        }
        int[] left = dfs(root.left);
        int[] right = dfs(root.right);

        int select = root.val + left[0] + right[0];
        int unselect = Math.max(left[0],left[1]) + Math.max(right[0],right[1]);
        return new int[]{
    
    unselect,select}; 
    }
}