# GeetCode Hub

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:

```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
```

Constraints:

• `1 <= word.length, prefix.length <= 2000`
• `word` and `prefix` consist only of lowercase English letters.
• At most `3 * 104` calls in total will be made to `insert`, `search`, and `startsWith`.

class Trie { /** Initialize your data structure here. */ public Trie() { } /** Inserts a word into the trie. */ public void insert(String word) { } /** Returns if the word is in the trie. */ public boolean search(String word) { } /** Returns if there is any word in the trie that starts with the given prefix. */ public boolean startsWith(String prefix) { } } /** * Your Trie object will be instantiated and called as such: * Trie obj = new Trie(); * obj.insert(word); * boolean param_2 = obj.search(word); * boolean param_3 = obj.startsWith(prefix); */
Medium