Lexicon - the maximum depth of a binary tree

Title description: Given a binary tree, find its maximum depth.

The depth of a binary tree is the number of nodes on the longest path from the root node to the farthest leaf node.

class Solution {public int maxDepth(TreeNode root) {if(root == null) return 0;int leftHeight = maxDepth(root.left);int rightHeight = maxDepth(root.right);return leftHeight>rightHeight?leftHeight+1:rightHeight+span>1;}}

Note:

return maxDepth(root.left)>maxDepth(root.right)?maxDepth(root.left)+1:maxDepth(root.right)+1;

The time complexity of this way of writing is very large, because it recurses the left subtree and the right subtree twice.