Medium
Implement a trie with insert(word), search(word) (returns whether the exact word was inserted), and startsWith(prefix) (returns whether any inserted word has the given prefix).
Input: operations = ["Trie","insert","search","search","startsWith","insert","search"], values = [[],["apple"],["apple"],["app"],["app"],["app"],["app"]] Output: [null,null,true,false,true,null,true]