【动态规划】打家劫舍

这是一到关于树的打家劫舍，我们采用dfs和动态规划的相互配合解决这道题，

/**
 * 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 {
    public int rob(TreeNode root) {
        int[] s = dfs(root);
        return Math.max(s[0],s[1]);

    }
    public int[] dfs(TreeNode node){
       if(node == null){
           return new int[]{0,0};
       }
       int l[] = dfs(node.left);
       int r[] = dfs(node.right);

       int select = node.val + l[1] + r[1];
       int nonselect = Math.max(l[0],l[1]) + Math.max(r[0],r[1]);

       return new int[]{select,nonselect}; 

    }
}