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.
class Solution {
public int maxDepth(TreeNode root) {
if (root == null)
return 0;
int left = maxDepth(root.left);
int right= maxDepth(root.right);
return 1 + Math.max(left, right);
}
}
104. Maximum Depth of Binary Tree
原文：https://www.cnblogs.com/MarkLeeBYR/p/10537314.html