Maximum Depth of Binary Tree | Leetcode

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.

---

Solution: Recurse down the tree, and return the maximum of the depth of the left and right sub-trees.

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