Medium

Quiz

#208 Implement Trie (Prefix Tree)

APPROACH

A prefix tree (trie, pronounced "try") enables efficient string storage and lookup, powering features like autocomplete and spell-check.

Build the Trie class:

- Trie() sets up an empty trie.

- void insert(String word) stores word in the trie.

- boolean search(String word) returns true if word was previously inserted.

- boolean startsWith(String prefix) returns true if any inserted word begins with prefix.

Example 1:

Input

["Trie", "insert", "search", "search", "startsWith", "insert", "search"]

[[], ["apple"], ["apple"], ["app"], ["app"], ["app"], ["app"]]

Output

[null, null, true, false, true, null, true]

Example 2:

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

1 of 4

1:00

What is the optimal approach for this problem?