怎么求一个二叉树的深度?手撕代码?

“`” 考察点：二叉树

<pre><code class=""language-java"" lang=""java"">public int maxDepth(TreeNode root) {
if (root == null) {
return 0;
}
int left = maxDepth(root.left);
int right = maxDepth(root.right);
int bigger = Math.max(left, right);
return bigger + 1;
}
</code></pre>

<pre><code> "“`