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.
1 //Time: O(n), Space: O(logn) recusive stack的空间 2 public int maxDepth(TreeNode root) { 3 if (root == null) { 4 return 0; 5 } 6 7 return 1 + Math.max(maxDepth(root.left), maxDepth(root.right)); 8 }
104. Maximum Depth of Binary Tree
原文：https://www.cnblogs.com/jessie2009/p/9762781.html