#+ANKI_DECK: study_deck_02
* TODO 0208. Implement Trie Prefix Tree :medium:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0208. Implement Trie Prefix Tree][0208. Implement Trie Prefix Tree]]
:END:

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.

*Example 1:*


#+begin_src
Input
["Trie", "insert", "search", "search", "startsWith", "insert", "search"]
[[], ["apple"], ["apple"], ["app"], ["app"], ["app"], ["app"]]
Output
[null, null, true, false, true, null, true]

Explanation
Trie trie = new Trie();
trie.insert("apple");
trie.search("apple");   // return True
trie.search("app");     // return False
trie.startsWith("app"); // return True
trie.insert("app");
trie.search("app");     // return True
#+end_src


*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 ~startsWith~.

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python
class Trie:

    def __init__(self):
        

    def insert(self, word: str) -> None:
        

    def search(self, word: str) -> bool:
        

    def startsWith(self, prefix: str) -> bool:
        


# Your Trie object will be instantiated and called as such:
# obj = Trie()
# obj.insert(word)
# param_2 = obj.search(word)
# param_3 = obj.startsWith(prefix)
#+end_src

** TODO C++
#+begin_src cpp
class Trie {
public:
    Trie() {
        
    }
    
    void insert(string word) {
        
    }
    
    bool search(string word) {
        
    }
    
    bool startsWith(string prefix) {
        
    }
};

/**
 * Your Trie object will be instantiated and called as such:
 * Trie* obj = new Trie();
 * obj->insert(word);
 * bool param_2 = obj->search(word);
 * bool param_3 = obj->startsWith(prefix);
 */
#+end_src