Implement Trie $-$ II

Problem Statement: Implement a data structure "TRIE" from scratch. Complete some functions.

Trie$()$: Initialize the object of this "TRIE" data structure.

insert$("$WORD$")$: Insert the string "WORD" into this "TRIE" data structure.

countWordsEqualTo$("$WORD$")$: Return how many times this "WORD" is present in this "TRIE".

countWordsStartingWith$("$PREFIX$")$: Return how many words are there in this "TRIE" that have the string "PREFIX" as a

prefix.

erase$("$WORD$")$: Delete this string "WORD" from the "TRIE".