{ "data": { "question": { "questionId": "208", "questionFrontendId": "208", "boundTopicId": null, "title": "Implement Trie (Prefix Tree)", "titleSlug": "implement-trie-prefix-tree", "content": "

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.

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Implement the Trie class:

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Example 1:

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\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\nExplanation\nTrie trie = new Trie();\ntrie.insert("apple");\ntrie.search("apple");   // return True\ntrie.search("app");     // return False\ntrie.startsWith("app"); // return True\ntrie.insert("app");\ntrie.search("app");     // return True\n
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Constraints:

\n\n\n", "translatedTitle": null, "translatedContent": null, "isPaidOnly": false, "difficulty": "Medium", "likes": 6845, "dislikes": 91, "isLiked": null, "similarQuestions": "[{\"title\": \"Design Add and Search Words Data Structure\", \"titleSlug\": \"design-add-and-search-words-data-structure\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Design Search Autocomplete System\", \"titleSlug\": \"design-search-autocomplete-system\", \"difficulty\": \"Hard\", \"translatedTitle\": null}, {\"title\": \"Replace Words\", \"titleSlug\": \"replace-words\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Implement Magic Dictionary\", \"titleSlug\": \"implement-magic-dictionary\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Encrypt and Decrypt Strings\", \"titleSlug\": \"encrypt-and-decrypt-strings\", \"difficulty\": \"Hard\", \"translatedTitle\": null}, {\"title\": \"Implement Trie II (Prefix Tree)\", \"titleSlug\": \"implement-trie-ii-prefix-tree\", \"difficulty\": \"Medium\", \"translatedTitle\": null}]", "exampleTestcases": "[\"Trie\",\"insert\",\"search\",\"search\",\"startsWith\",\"insert\",\"search\"]\n[[],[\"apple\"],[\"apple\"],[\"app\"],[\"app\"],[\"app\"],[\"app\"]]", "categoryTitle": "Algorithms", "contributors": [], "topicTags": [ { "name": "Hash Table", "slug": "hash-table", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "String", "slug": "string", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Design", "slug": "design", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Trie", "slug": "trie", "translatedName": null, "__typename": "TopicTagNode" } ], "companyTagStats": null, "codeSnippets": [ { "lang": "C++", "langSlug": "cpp", "code": "class Trie {\npublic:\n Trie() {\n \n }\n \n void insert(string word) {\n \n }\n \n bool search(string word) {\n \n }\n \n bool startsWith(string prefix) {\n \n }\n};\n\n/**\n * Your Trie object will be instantiated and called as such:\n * Trie* obj = new Trie();\n * obj->insert(word);\n * bool param_2 = obj->search(word);\n * bool param_3 = obj->startsWith(prefix);\n */", "__typename": "CodeSnippetNode" }, { "lang": "Java", "langSlug": "java", "code": "class Trie {\n\n public Trie() {\n \n }\n \n public void insert(String word) {\n \n }\n \n public boolean search(String word) {\n \n }\n \n public boolean startsWith(String prefix) {\n \n }\n}\n\n/**\n * Your Trie object will be instantiated and called as such:\n * Trie obj = new Trie();\n * obj.insert(word);\n * boolean param_2 = obj.search(word);\n * boolean param_3 = obj.startsWith(prefix);\n */", "__typename": "CodeSnippetNode" }, { "lang": "Python", "langSlug": "python", "code": "class Trie(object):\n\n def __init__(self):\n \n\n def insert(self, word):\n \"\"\"\n :type word: str\n :rtype: None\n \"\"\"\n \n\n def search(self, word):\n \"\"\"\n :type word: str\n :rtype: bool\n \"\"\"\n \n\n def startsWith(self, prefix):\n \"\"\"\n :type prefix: str\n :rtype: bool\n \"\"\"\n \n\n\n# Your Trie object will be instantiated and called as such:\n# obj = Trie()\n# obj.insert(word)\n# param_2 = obj.search(word)\n# param_3 = obj.startsWith(prefix)", "__typename": "CodeSnippetNode" }, { "lang": "Python3", "langSlug": "python3", "code": "class Trie:\n\n def __init__(self):\n \n\n def insert(self, word: str) -> None:\n \n\n def search(self, word: str) -> bool:\n \n\n def startsWith(self, prefix: str) -> bool:\n \n\n\n# Your Trie object will be instantiated and called as such:\n# obj = Trie()\n# obj.insert(word)\n# param_2 = obj.search(word)\n# param_3 = obj.startsWith(prefix)", "__typename": "CodeSnippetNode" }, { "lang": "C", "langSlug": "c", "code": "\n\n\ntypedef struct {\n \n} Trie;\n\n\nTrie* trieCreate() {\n \n}\n\nvoid trieInsert(Trie* obj, char * word) {\n \n}\n\nbool trieSearch(Trie* obj, char * word) {\n \n}\n\nbool trieStartsWith(Trie* obj, char * prefix) {\n \n}\n\nvoid trieFree(Trie* obj) {\n \n}\n\n/**\n * Your Trie struct will be instantiated and called as such:\n * Trie* obj = trieCreate();\n * trieInsert(obj, word);\n \n * bool param_2 = trieSearch(obj, word);\n \n * bool param_3 = trieStartsWith(obj, prefix);\n \n * trieFree(obj);\n*/", "__typename": "CodeSnippetNode" }, { "lang": "C#", "langSlug": "csharp", "code": "public class Trie {\n\n public Trie() {\n \n }\n \n public void Insert(string word) {\n \n }\n \n public bool Search(string word) {\n \n }\n \n public bool StartsWith(string prefix) {\n \n }\n}\n\n/**\n * Your Trie object will be instantiated and called as such:\n * Trie obj = new Trie();\n * obj.Insert(word);\n * bool param_2 = obj.Search(word);\n * bool param_3 = obj.StartsWith(prefix);\n */", "__typename": "CodeSnippetNode" }, { "lang": "JavaScript", "langSlug": "javascript", "code": "\nvar Trie = function() {\n \n};\n\n/** \n * @param {string} word\n * @return {void}\n */\nTrie.prototype.insert = function(word) {\n \n};\n\n/** \n * @param {string} word\n * @return {boolean}\n */\nTrie.prototype.search = function(word) {\n \n};\n\n/** \n * @param {string} prefix\n * @return {boolean}\n */\nTrie.prototype.startsWith = function(prefix) {\n \n};\n\n/** \n * Your Trie object will be instantiated and called as such:\n * var obj = new Trie()\n * obj.insert(word)\n * var param_2 = obj.search(word)\n * var param_3 = obj.startsWith(prefix)\n */", "__typename": "CodeSnippetNode" }, { "lang": "Ruby", "langSlug": "ruby", "code": "class Trie\n def initialize()\n \n end\n\n\n=begin\n :type word: String\n :rtype: Void\n=end\n def insert(word)\n \n end\n\n\n=begin\n :type word: String\n :rtype: Boolean\n=end\n def search(word)\n \n end\n\n\n=begin\n :type prefix: String\n :rtype: Boolean\n=end\n def starts_with(prefix)\n \n end\n\n\nend\n\n# Your Trie object will be instantiated and called as such:\n# obj = Trie.new()\n# obj.insert(word)\n# param_2 = obj.search(word)\n# param_3 = obj.starts_with(prefix)", "__typename": "CodeSnippetNode" }, { "lang": "Swift", "langSlug": "swift", "code": "\nclass Trie {\n\n init() {\n \n }\n \n func insert(_ word: String) {\n \n }\n \n func search(_ word: String) -> Bool {\n \n }\n \n func startsWith(_ prefix: String) -> Bool {\n \n }\n}\n\n/**\n * Your Trie object will be instantiated and called as such:\n * let obj = Trie()\n * obj.insert(word)\n * let ret_2: Bool = obj.search(word)\n * let ret_3: Bool = obj.startsWith(prefix)\n */", "__typename": "CodeSnippetNode" }, { "lang": "Go", "langSlug": "golang", "code": "type Trie struct {\n \n}\n\n\nfunc Constructor() Trie {\n \n}\n\n\nfunc (this *Trie) Insert(word string) {\n \n}\n\n\nfunc (this *Trie) Search(word string) bool {\n \n}\n\n\nfunc (this *Trie) StartsWith(prefix string) bool {\n \n}\n\n\n/**\n * Your Trie object will be instantiated and called as such:\n * obj := Constructor();\n * obj.Insert(word);\n * param_2 := obj.Search(word);\n * param_3 := obj.StartsWith(prefix);\n */", "__typename": "CodeSnippetNode" }, { "lang": "Scala", "langSlug": "scala", "code": "class Trie() {\n\n def insert(word: String) {\n \n }\n\n def search(word: String): Boolean = {\n \n }\n\n def startsWith(prefix: String): Boolean = {\n \n }\n\n}\n\n/**\n * Your Trie object will be instantiated and called as such:\n * var obj = new Trie()\n * obj.insert(word)\n * var param_2 = obj.search(word)\n * var param_3 = obj.startsWith(prefix)\n */", "__typename": "CodeSnippetNode" }, { "lang": "Kotlin", "langSlug": "kotlin", "code": "class Trie() {\n\n fun insert(word: String) {\n \n }\n\n fun search(word: String): Boolean {\n \n }\n\n fun startsWith(prefix: String): Boolean {\n \n }\n\n}\n\n/**\n * Your Trie object will be instantiated and called as such:\n * var obj = Trie()\n * obj.insert(word)\n * var param_2 = obj.search(word)\n * var param_3 = obj.startsWith(prefix)\n */", "__typename": "CodeSnippetNode" }, { "lang": "Rust", "langSlug": "rust", "code": "struct Trie {\n\n}\n\n\n/** \n * `&self` means the method takes an immutable reference.\n * If you need a mutable reference, change it to `&mut self` instead.\n */\nimpl Trie {\n\n fn new() -> Self {\n \n }\n \n fn insert(&self, word: String) {\n \n }\n \n fn search(&self, word: String) -> bool {\n \n }\n \n fn starts_with(&self, prefix: String) -> bool {\n \n }\n}\n\n/**\n * Your Trie object will be instantiated and called as such:\n * let obj = Trie::new();\n * obj.insert(word);\n * let ret_2: bool = obj.search(word);\n * let ret_3: bool = obj.starts_with(prefix);\n */", "__typename": "CodeSnippetNode" }, { "lang": "PHP", "langSlug": "php", "code": "class Trie {\n /**\n */\n function __construct() {\n \n }\n \n /**\n * @param String $word\n * @return NULL\n */\n function insert($word) {\n \n }\n \n /**\n * @param String $word\n * @return Boolean\n */\n function search($word) {\n \n }\n \n /**\n * @param String $prefix\n * @return Boolean\n */\n function startsWith($prefix) {\n \n }\n}\n\n/**\n * Your Trie object will be instantiated and called as such:\n * $obj = Trie();\n * $obj->insert($word);\n * $ret_2 = $obj->search($word);\n * $ret_3 = $obj->startsWith($prefix);\n */", "__typename": "CodeSnippetNode" }, { "lang": "TypeScript", "langSlug": "typescript", "code": "class Trie {\n constructor() {\n\n }\n\n insert(word: string): void {\n\n }\n\n search(word: string): boolean {\n\n }\n\n startsWith(prefix: string): boolean {\n\n }\n}\n\n/**\n * Your Trie object will be instantiated and called as such:\n * var obj = new Trie()\n * obj.insert(word)\n * var param_2 = obj.search(word)\n * var param_3 = obj.startsWith(prefix)\n */", "__typename": "CodeSnippetNode" }, { "lang": "Racket", "langSlug": "racket", "code": "(define trie%\n (class object%\n (super-new)\n (init-field)\n \n ; insert : string? -> void?\n (define/public (insert word)\n\n )\n ; search : string? -> boolean?\n (define/public (search word)\n\n )\n ; starts-with : string? -> boolean?\n (define/public (starts-with prefix)\n\n )))\n\n;; Your trie% object will be instantiated and called as such:\n;; (define obj (new trie%))\n;; (send obj insert word)\n;; (define param_2 (send obj search word))\n;; (define param_3 (send obj starts-with prefix))", "__typename": "CodeSnippetNode" }, { "lang": "Erlang", "langSlug": "erlang", "code": "-spec trie_init_() -> any().\ntrie_init_() ->\n .\n\n-spec trie_insert(Word :: unicode:unicode_binary()) -> any().\ntrie_insert(Word) ->\n .\n\n-spec trie_search(Word :: unicode:unicode_binary()) -> boolean().\ntrie_search(Word) ->\n .\n\n-spec trie_starts_with(Prefix :: unicode:unicode_binary()) -> boolean().\ntrie_starts_with(Prefix) ->\n .\n\n\n%% Your functions will be called as such:\n%% trie_init_(),\n%% trie_insert(Word),\n%% Param_2 = trie_search(Word),\n%% Param_3 = trie_starts_with(Prefix),\n\n%% trie_init_ will be called before every test case, in which you can do some necessary initializations.", "__typename": "CodeSnippetNode" }, { "lang": "Elixir", "langSlug": "elixir", "code": "defmodule Trie do\n @spec init_() :: any\n def 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