feat: add trie problem and dict_tree

Author: wislertt

.templates/leetcode/json/implement_trie_prefix_tree.json

@@ -0,0 +1,45 @@
+{
+    "problem_name": "implement_trie_prefix_tree",
+    "solution_class_name": "Trie",
+    "problem_number": "208",
+    "problem_title": "Implement Trie (Prefix Tree)",
+    "difficulty": "Medium",
+    "topics": "Hash Table, String, Design, Trie",
+    "tags": ["grind-75"],
+    "readme_description": "A **trie** (pronounced as \"try\") or **prefix tree** is a tree data structure used to efficiently store and retrieve keys in a dataset of strings. There are various applications of this data structure, such as autocomplete and spellchecker.\n\nImplement the Trie class:\n\n- `Trie()` Initializes the trie object.\n- `void insert(String word)` Inserts the string `word` into the trie.\n- `boolean search(String word)` Returns `true` if the string `word` is in the trie (i.e., was inserted before), and `false` otherwise.\n- `boolean startsWith(String prefix)` Returns `true` if there is a previously inserted string `word` that has the prefix `prefix`, and `false` otherwise.",
+    "readme_examples": [
+        {
+            "content": "```\nInput\n[\"Trie\", \"insert\", \"search\", \"search\", \"startsWith\", \"insert\", \"search\"]\n[[], [\"apple\"], [\"apple\"], [\"app\"], [\"app\"], [\"app\"], [\"app\"]]\nOutput\n[null, null, true, false, true, null, true]\n```\n\n**Explanation:**\n```python\ntrie = Trie()\ntrie.insert(\"apple\")\ntrie.search(\"apple\")    # return True\ntrie.search(\"app\")      # return False\ntrie.starts_with(\"app\") # return True\ntrie.insert(\"app\")\ntrie.search(\"app\")      # return True\n```"
+        }
+    ],
+    "readme_constraints": "- `1 <= word.length, prefix.length <= 2000`\n- `word` and `prefix` consist only of lowercase English letters.\n- At most `3 * 10^4` calls **in total** will be made to `insert`, `search`, and `starts_with`.",
+    "readme_additional": "",
+    "solution_imports": "",
+    "solution_methods": [
+        { "name": "__init__", "parameters": "", "return_type": "None", "dummy_return": "" },
+        { "name": "insert", "parameters": "word: str", "return_type": "None", "dummy_return": "" },
+        { "name": "search", "parameters": "word: str", "return_type": "bool", "dummy_return": "False" },
+        {
+            "name": "starts_with",
+            "parameters": "prefix: str",
+            "return_type": "bool",
+            "dummy_return": "False"
+        }
+    ],
+    "test_imports": "import pytest\nfrom leetcode_py.test_utils import logged_test\nfrom .solution import Trie",
+    "test_class_name": "ImplementTriePrefixTree",
+    "test_helper_methods": [],
+    "test_methods": [
+        {
+            "name": "test_trie_operations",
+            "parametrize": "operations, inputs, expected",
+            "parametrize_typed": "operations: list[str], inputs: list[list[str]], expected: list[bool | None]",
+            "test_cases": "[(['Trie', 'insert', 'search', 'search', 'starts_with', 'insert', 'search'], [[], ['apple'], ['apple'], ['app'], ['app'], ['app'], ['app']], [None, None, True, False, True, None, True]), (['Trie', 'insert', 'insert', 'search', 'search', 'starts_with', 'starts_with'], [[], ['hello'], ['world'], ['hello'], ['hi'], ['hel'], ['wor']], [None, None, None, True, False, True, True]), (['Trie', 'insert', 'insert', 'search', 'search', 'starts_with', 'starts_with'], [[], ['a'], ['aa'], ['a'], ['aa'], ['a'], ['aa']], [None, None, None, True, True, True, True]), (['Trie', 'insert', 'search', 'starts_with', 'insert', 'search', 'starts_with'], [[], ['test'], ['testing'], ['test'], ['testing'], ['testing'], ['test']], [None, None, False, True, None, True, True]), (['Trie', 'search', 'starts_with'], [[], ['empty'], ['empty']], [None, False, False])]",
+            "body": "trie: Trie | None = None\nresults: list[bool | None] = []\nfor i, op in enumerate(operations):\n    if op == 'Trie':\n        trie = Trie()\n        results.append(None)\n    elif op == 'insert' and trie is not None:\n        trie.insert(inputs[i][0])\n        results.append(None)\n    elif op == 'search' and trie is not None:\n        results.append(trie.search(inputs[i][0]))\n    elif op == 'starts_with' and trie is not None:\n        results.append(trie.starts_with(inputs[i][0]))\nassert results == expected"
+        }
+    ],
+    "playground_imports": "from solution import Trie",
+    "playground_test_case": "# Example test case\noperations = ['Trie', 'insert', 'search', 'search', 'starts_with', 'insert', 'search']\ninputs = [[], ['apple'], ['apple'], ['app'], ['app'], ['app'], ['app']]\nexpected = [None, None, True, False, True, None, True]",
+    "playground_execution": "trie = None\nresults: list[bool | None] = []\nfor i, op in enumerate(operations):\n    if op == 'Trie':\n        trie = Trie()\n        results.append(None)\n    elif op == 'insert' and trie is not None:\n        trie.insert(inputs[i][0])\n        results.append(None)\n    elif op == 'search' and trie is not None:\n        results.append(trie.search(inputs[i][0]))\n    elif op == 'starts_with' and trie is not None:\n        results.append(trie.starts_with(inputs[i][0]))\nresults",
+    "playground_assertion": "assert results == expected"
+}

Makefile

@@ -1,5 +1,5 @@
 PYTHON_VERSION = 3.13
-PROBLEM ?= maximum_profit_in_job_scheduling
+PROBLEM ?= implement_trie_prefix_tree
 FORCE ?= 0
 COMMA := ,
 

leetcode/implement_trie_prefix_tree/README.md

@@ -0,0 +1,48 @@
+# Implement Trie (Prefix Tree)
+
+**Difficulty:** Medium
+**Topics:** Hash Table, String, Design, Trie
+**Tags:** grind-75
+
+**LeetCode:** [Problem 208](https://leetcode.com/problems/implement-trie-prefix-tree/description/)
+
+## Problem Description
+
+A **trie** (pronounced as "try") or **prefix tree** is a tree data structure used to efficiently store and retrieve keys in a dataset of strings. There are various applications of this data structure, such as autocomplete and spellchecker.
+
+Implement the Trie class:
+
+- `Trie()` Initializes the trie object.
+- `void insert(String word)` Inserts the string `word` into the trie.
+- `boolean search(String word)` Returns `true` if the string `word` is in the trie (i.e., was inserted before), and `false` otherwise.
+- `boolean startsWith(String prefix)` Returns `true` if there is a previously inserted string `word` that has the prefix `prefix`, and `false` otherwise.
+
+## Examples
+
+### Example 1:
+
+```
+Input
+["Trie", "insert", "search", "search", "startsWith", "insert", "search"]
+[[], ["apple"], ["apple"], ["app"], ["app"], ["app"], ["app"]]
+Output
+[null, null, true, false, true, null, true]
+```
+
+**Explanation:**
+
+```python
+trie = Trie()
+trie.insert("apple")
+trie.search("apple")    # return True
+trie.search("app")      # return False
+trie.starts_with("app") # return True
+trie.insert("app")
+trie.search("app")      # return True
+```
+
+## Constraints
+
+- `1 <= word.length, prefix.length <= 2000`
+- `word` and `prefix` consist only of lowercase English letters.
+- At most `3 * 10^4` calls **in total** will be made to `insert`, `search`, and `starts_with`.

leetcode/implement_trie_prefix_tree/__init__.py

@@ -0,0 +1,217 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "imports",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from solution import Trie"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "setup",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Example test case\n",
+    "operations = [\"Trie\", \"insert\", \"search\", \"search\", \"starts_with\", \"insert\", \"search\"]\n",
+    "inputs = [[], [\"apple\"], [\"apple\"], [\"app\"], [\"app\"], [\"app\"], [\"app\"]]\n",
+    "expected = [None, None, True, False, True, None, True]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "execute",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[None, None, True, False, True, None, True]"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "trie = None\n",
+    "results: list[bool | None] = []\n",
+    "for i, op in enumerate(operations):\n",
+    "    if op == \"Trie\":\n",
+    "        trie = Trie()\n",
+    "        results.append(None)\n",
+    "    elif op == \"insert\" and trie is not None:\n",
+    "        trie.insert(inputs[i][0])\n",
+    "        results.append(None)\n",
+    "    elif op == \"search\" and trie is not None:\n",
+    "        results.append(trie.search(inputs[i][0]))\n",
+    "    elif op == \"starts_with\" and trie is not None:\n",
+    "        results.append(trie.starts_with(inputs[i][0]))\n",
+    "results"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "8d00661e",
+   "metadata": {},
+   "outputs": [
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+      ]
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+     "metadata": {},
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+    }
+   ],
+   "source": [
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+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "test",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "assert results == expected"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "leetcode-py-py3.13",
+   "language": "python",
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+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

leetcode/implement_trie_prefix_tree/playground.ipynb

@@ -0,0 +1,42 @@
+from typing import Any
+
+from leetcode_py.data_structures import DictTree
+
+
+class Trie(DictTree[str]):
+    END_OF_WORD = "#"
+
+    # Time: O(1)
+    # Space: O(1)
+    def __init__(self) -> None:
+        self.root: dict[str, Any] = {}
+
+    # Time: O(m) where m is word length
+    # Space: O(m)
+    def insert(self, word: str) -> None:
+        node = self.root
+        for char in word:
+            if char not in node:
+                node[char] = {}
+            node = node[char]
+        node[self.END_OF_WORD] = True  # End of word marker
+
+    # Time: O(m) where m is word length
+    # Space: O(1)
+    def search(self, word: str) -> bool:
+        node = self.root
+        for char in word:
+            if char not in node:
+                return False
+            node = node[char]
+        return self.END_OF_WORD in node
+
+    # Time: O(m) where m is prefix length
+    # Space: O(1)
+    def starts_with(self, prefix: str) -> bool:
+        node = self.root
+        for char in prefix:
+            if char not in node:
+                return False
+            node = node[char]
+        return True