题解 | #二叉树的最大深度#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 * }
 */

public class Solution {
    /**
    * @param root TreeNode类
    * @return int整型
    */
    public int maxDepth(TreeNode root) {
        // write code here
        if (root == null) {
            return 0;
        }

        return dept(root, 0);
    }

    public int dept(TreeNode root, Integer dept) {
        // 搜索到最底层，返回深度
        if (root == null) {
            return dept;
        }
        // 先左
        int leftDept = dept(root.left, dept + 1);
        // 再右
        int rightDept = dept(root.right, dept + 1);

        return Integer.max(leftDept, rightDept);
    }
}