题目描述

输入一棵二叉树，求该树的深度。从根结点到叶结点依次经过的结点（含根、叶结点）形成树的一条路径，最长路径的长度为树的深度。

题目链接：​​牛客网​​

解题思路

public class Main {
    public static class TreeNode {
        int val = 0;
        TreeNode left = null;
        TreeNode right = null;

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

        }

    }
    
    public static void main(String[] args) {
        TreeNode root = new TreeNode(1);
        root.right = new TreeNode(3);
        root.left = new TreeNode(2);
        root.left.left = new TreeNode(4);
        root.left.right = new TreeNode(5);
        root.left.right.left = new TreeNode(7);
        
        System.out.println(treeDepth(root));
    }
    
    public static int treeDepth(TreeNode root) {
        return root == null ? 0 : 1 + Math.max(treeDepth(root.left), treeDepth(root.right));
    }
}

测试结果