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Leetcode
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Trees
Recursion
Queues
Maximum Depth Of Binary Tree

Find the number of nodes on the longest root-to-leaf path in a binary tree.

Acceptance 100%
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Problem Statement

Given the root of a binary tree, determine its maximum depth. The maximum depth is the number of nodes along the longest path from the root down to any leaf node.

A leaf is a node with no children.

Input Format

  • A binary tree root node.
  • Each node contains an integer value and references to left and right children.

Output Format

  • Return a single integer representing the maximum depth of the tree.

Constraints

  • The tree may be empty.
  • The tree can be highly unbalanced.
  • Solve efficiently using tree traversal.
Examples
Sample cases returned by the problem API.

Example 1

Input

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

Output

3

Explanation

The longest path is 3 -> 20 -> 15 (or 3 -> 20 -> 7), which has 3 nodes.

Example 2

Input

root = [1,null,2]

Output

2

Explanation

The longest path is 1 -> 2, so the maximum depth is 2.

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