Solution Review: Word Formation From a Vector Using a Trie

using System;
using System.Collections.Generic;
using System.Text;
namespace chapter_7
{
    class Program
    {
        static bool isFormationPossible(List<string> list, string word)
        {
            //Create Trie and insert vector elements in it
            Trie trie = new Trie();
            for (int x = 0; x < list.Count; x++)
            {
                trie.insertNode(list[x]);
            }
            TrieNode currentNode = trie.getRoot();
            for (int i = 0; i < word.Length; i++)
            {
                char index = (Char)trie.getIndex(word[i]);
                // if the prefix of word does not exist, word would not either
                if (currentNode.children[index] == null)
                {
                    return false;
                }
                // if the substring of the word exists as a word in trie, check whether rest of the word also exists, if it does return true
                else if ((currentNode.children[index].isEndWord == true) && trie.searchNode(word.Substring(i + 1)))
                {
                    return true;
                }
                currentNode = currentNode.children[index];
            }
            return false;
        }
        static void Main(string[] args)
        {
            List<string> keys = new List<string>{ "he", "hello", "loworld", "friend" };
            if (isFormationPossible(keys, "helloworld"))
                Console.WriteLine("true");
            else
                Console.WriteLine("false");
            if (isFormationPossible(keys, "hellofriend"))
                Console.WriteLine("true");
            else
                Console.WriteLine("false");
            return;
        }
    }
}