# 104. Maximum Depth of Binary Tree

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

**Note:** A leaf is a node with no children.

**Example:**

Given binary tree `[3,9,20,null,null,15,7]`

,

3 / \ 9 20 / \ 15 7

return its depth = 3.

#### Thought:

Nothing special but..

**I’m using Java this time..**

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ class Solution { public int maxDepth(TreeNode root) { return maxDepthHelper(root, 0); } public int maxDepthHelper(TreeNode node, int depth) { if(node != null){ return Math.max(maxDepthHelper(node.left, depth+1) , maxDepthHelper(node.right, depth+1)); } return depth; } }

## 0 Comments