Implement a trie with these operations:
Trie(): Initialize the trieinsert(word): Insert a word into the triesearch(word): Return true if word is in the triestartsWith(prefix): Return true if any word starts with prefix
Example:
trie.insert("apple")
trie.search("apple") // true
trie.search("app") // false
trie.startsWith("app") // true
Constraints: words and prefixes consist of lowercase letters, length 1-2000, up to operations total.