104

104. Maximum Depth of Binary Tree (Easy)

Given the root of a binary tree, return its maximum depth.

A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

 

Example 1:

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

Example 2:

Input: root = [1,null,2]
Output: 2

 

Constraints:

• The number of nodes in the tree is in the range [0, 104].
• -100 <= Node.val <= 100

Companies:
LinkedIn, Amazon, Google, Spotify, Microsoft

Related Topics:
Tree, Depth-First Search, Breadth-First Search, Binary Tree

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Solution 1.

// OJ: https://leetcode.com/problems/maximum-depth-of-binary-tree/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(N)
class Solution {
public:
    int maxDepth(TreeNode* root) {
        return root ? 1 + max(maxDepth(root->left), maxDepth(root->right)) : 0;
    }
};