feat: add max depth binary tree

Author: wislertt

.templates/leetcode/json/maximum_depth_of_binary_tree.json

@@ -0,0 +1,45 @@
+{
+    "problem_name": "maximum_depth_of_binary_tree",
+    "solution_class_name": "Solution",
+    "problem_number": "104",
+    "problem_title": "Maximum Depth of Binary Tree",
+    "difficulty": "Easy",
+    "topics": "Tree, Depth-First Search, Breadth-First Search, Binary Tree",
+    "tags": ["grind-75"],
+    "readme_description": "Given the `root` of a binary tree, return *its maximum depth*.\n\nA binary tree's **maximum depth** is the number of nodes along the longest path from the root node down to the farthest leaf node.",
+    "readme_examples": [
+        {
+            "content": "![Example 1](https://assets.leetcode.com/uploads/2020/11/26/tmp-tree.jpg)\n\n```\nInput: root = [3,9,20,null,null,15,7]\nOutput: 3\n```"
+        },
+        { "content": "```\nInput: root = [1,null,2]\nOutput: 2\n```" }
+    ],
+    "readme_constraints": "- The number of nodes in the tree is in the range `[0, 10^4]`.\n- `-100 <= Node.val <= 100`",
+    "readme_additional": "",
+    "solution_imports": "from leetcode_py import TreeNode",
+    "solution_methods": [
+        {
+            "name": "max_depth",
+            "parameters": "root: TreeNode[int] | None",
+            "return_type": "int",
+            "dummy_return": "0"
+        }
+    ],
+    "test_imports": "import pytest\nfrom leetcode_py.test_utils import logged_test\nfrom leetcode_py import TreeNode\nfrom .solution import Solution",
+    "test_class_name": "MaximumDepthOfBinaryTree",
+    "test_helper_methods": [
+        { "name": "setup_method", "parameters": "", "body": "self.solution = Solution()" }
+    ],
+    "test_methods": [
+        {
+            "name": "test_max_depth",
+            "parametrize": "root_list, expected",
+            "parametrize_typed": "root_list: list[int | None], expected: int",
+            "test_cases": "[([3, 9, 20, None, None, 15, 7], 3), ([1, None, 2], 2), ([], 0)]",
+            "body": "root = TreeNode.from_list(root_list)\nresult = self.solution.max_depth(root)\nassert result == expected"
+        }
+    ],
+    "playground_imports": "from solution import Solution\nfrom leetcode_py import TreeNode",
+    "playground_test_case": "# Example test case\nroot_list = [3, 9, 20, None, None, 15, 7]\nexpected = 3",
+    "playground_execution": "root = TreeNode.from_list(root_list)\nresult = Solution().max_depth(root)\nresult",
+    "playground_assertion": "assert result == expected"
+}

Makefile

@@ -1,5 +1,5 @@
 PYTHON_VERSION = 3.13
-PROBLEM ?= string_to_integer_atoi
+PROBLEM ?= maximum_depth_of_binary_tree
 FORCE ?= 0
 COMMA := ,
 

leetcode/maximum_depth_of_binary_tree/README.md

@@ -0,0 +1,36 @@
+# Maximum Depth of Binary Tree
+
+**Difficulty:** Easy
+**Topics:** Tree, Depth-First Search, Breadth-First Search, Binary Tree
+**Tags:** grind-75
+
+**LeetCode:** [Problem 104](https://leetcode.com/problems/maximum-depth-of-binary-tree/description/)
+
+## Problem Description
+
+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.
+
+## Examples
+
+### Example 1:
+
+![Example 1](https://assets.leetcode.com/uploads/2020/11/26/tmp-tree.jpg)
+
+```
+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, 10^4]`.
+- `-100 <= Node.val <= 100`

leetcode/maximum_depth_of_binary_tree/__init__.py

@@ -0,0 +1,171 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "imports",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from solution import Solution\n",
+    "\n",
+    "from leetcode_py import TreeNode"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "setup",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Example test case\n",
+    "root_list = [3, 9, 20, None, None, 15, 7]\n",
+    "expected = 3"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "execute",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "3"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "root = TreeNode.from_list(root_list)\n",
+    "result = Solution().max_depth(root)\n",
+    "result"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "3d476584",
+   "metadata": {},
+   "outputs": [
+    {
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+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "test",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "assert result == expected"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
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+ },
+ "nbformat": 4,
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+}

leetcode/maximum_depth_of_binary_tree/playground.ipynb

@@ -0,0 +1,14 @@
+from leetcode_py import TreeNode
+
+
+class Solution:
+    # Time: O(n)
+    # Space: O(h)
+    def max_depth(self, root: TreeNode | None) -> int:
+        if not root:
+            return 0
+
+        left_depth = self.max_depth(root.left)
+        right_depth = self.max_depth(root.right)
+
+        return 1 + max(left_depth, right_depth)

leetcode/maximum_depth_of_binary_tree/solution.py

@@ -0,0 +1,39 @@
+import pytest
+
+from leetcode_py import TreeNode
+from leetcode_py.test_utils import logged_test
+
+from .solution import Solution
+
+
+class TestMaximumDepthOfBinaryTree:
+    def setup_method(self):
+        self.solution = Solution()
+
+    @pytest.mark.parametrize(
+        "root_list, expected",
+        [
+            # Original examples
+            ([3, 9, 20, None, None, 15, 7], 3),
+            ([1, None, 2], 2),
+            ([], 0),
+            # Single node
+            ([1], 1),
+            # Left skewed tree (depth 3)
+            ([1, 2, None, 3], 3),
+            # Right skewed tree (depth 2)
+            ([1, None, 2], 2),
+            # Balanced tree
+            ([1, 2, 3, 4, 5, 6, 7], 3),
+            # Unbalanced tree (left heavy)
+            ([1, 2, 3, 4, 5, None, None, 6, 7], 4),
+            # Two nodes
+            ([1, 2], 2),
+            ([1, None, 2], 2),
+        ],
+    )
+    @logged_test
+    def test_max_depth(self, root_list: list[int | None], expected: int):
+        root = TreeNode.from_list(root_list)
+        result = self.solution.max_depth(root)
+        assert result == expected