题解 | #二叉树的深度#

import java.util.*;
/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    //递归
    public int TreeDepth(TreeNode root) {
        if(root == null){
            return 0;
        }
        //求最大深度=求根的高度 ，求高度用后序遍历 左右根
        int leftHeight = 1 + TreeDepth(root.left);//左
        int rightHeight = 1 + TreeDepth(root.right);//右
        int maxHeight = Math.max(leftHeight,rightHeight);//中
        return maxHeight;

        //简化
        //return Math.max(maxDepth(root.left), maxDepth(root.right)) + 1;
	   //更简化
        //return root == null?0:Math.max(maxDepth(root.left), maxDepth(root.right)) + 1;
    }
}