EasyTrees

Maximum Depth of Binary Tree

treerecursiondfs

Problem

Given the root of a binary tree, return its maximum depth — the number of nodes along the longest path from the root node down to the farthest leaf node.

Examples

Example 1

Input: root = [3,9,20,null,null,15,7]

Output: 3

Constraints

•The number of nodes is in the range [0, 10^4].

Hints

Hint 1

Recursion: depth = 1 + max(depth(left), depth(right))

Solutions

public int maxDepth(TreeNode root) {
    if (root == null) return 0;
    return 1 + Math.max(maxDepth(root.left), maxDepth(root.right));
}

Java

Time: O(n) · Space: O(h)