Understanding Trie Data Structure

Trie, also known as a prefix tree, is a tree-like data structure that proves very efficient for solving problems related to strings. If you’re dealing with scenarios where you have to search for strings, a Trie can be faster than hashing and BSTs.

What is a Trie?

A Trie is a special type of tree used to store associative data structures. Storing strings in a Trie allows us to quickly find words, retrieve them, and prefix them. Each node of the Trie consists of multiple branches, each representing a possible character of keys. We mark the last node of every key as the end of the word node.

Implementing a Trie in Java

Let’s start by creating a TrieNode class:

class TrieNode {
    TrieNode[] children = new TrieNode[26];
    boolean isEndOfWord;
    
    TrieNode(){
        isEndOfWord = false;
        for (int i = 0; i < 26; i++)
            children[i] = null;
    }
};

In this class, children is an array storing all child nodes that can be accessed using characters ‘a’-‘z’. isEndOfWord is a boolean field and is true if the node represents the end of a word.

Insertion in Trie

To insert a key into the Trie, we insert one character at a time. We start from the root, and for…