HackerRank - The hidden message - study code

TheHiddenMessage2.cs

using System;
using System.Collections.Generic;
using System.IO;
public class ResultInfo
    {
        public int Start { get; set; }

        public string Word { get; set; }
    }

    public class TrieNode
    {
        public int Words { get; private set; }

        public int Prefixes { get; private set; }

        TrieNode[] edges;

        public string Word { get; private set; }

        public void Add(string word, int start)
        {
            TrieNode node = this;

            while (start < word.Length)
            {
                node.Prefixes++;
                int index = word[start] - 'a';
                if(node.edges == null)
                    node.edges = new TrieNode[26];
                if (node.edges[index] == null)
                {
                    node.edges[index] = new TrieNode();
                }
                node = node.edges[index];
                start++;
            }
            node.Words++;
            node.Prefixes++;
            node.Word = word;
        }

        public List<ResultInfo> FindWords(string s)
        {
            List<ResultInfo> result = new List<ResultInfo>();
            List<string> matches = new List<string>();
            for (int i = 0; i < s.Length; i++)
            {
                int count = result.Count;
                FindMatch(s, i, matches);

                for (int j = count; j < matches.Count; j++)
                {
                    result.Add(new ResultInfo {Start = i, Word = matches[j]});
                }
            }

            return result;
        }

        void FindMatch(string s, int i, List<string> matches)
        {
            var node = this;
            while (i < s.Length)
            {
                if (node.Word != null)
                    matches.Add(node.Word);
                int index = s[i] - 'a';
                if (node.edges == null || node.edges[index] == null)
                {
                    return;
                }
                node = node.edges[index];
                i++;
            }
            if(node.Word != null)
                matches.Add(node.Word);
        }
    }

class Solution {
    static void Main(String[] args) {
                    string t = Console.ReadLine();
            string p = Console.ReadLine();
            string[] phrase = p.Split(' ');
            TrieNode root = new TrieNode();
            foreach (string word in phrase)
            {
                root.Add(word, 0);
            }

            List<ResultInfo> matches = root.FindWords(t);
            Dictionary<string, List<int>> d = new Dictionary<string, List<int>>();

            foreach (var resultInfo in matches)
            {
                if (d.ContainsKey(resultInfo.Word))
                {
                    d[resultInfo.Word].Add(resultInfo.Start);
                }
                else
                {
                    var l = new List<int> {resultInfo.Start};
                    d.Add(resultInfo.Word, l);
                }
            }

            int[] phraseMatch = new int[phrase.Length];
            for (int i = 0; i < phraseMatch.Length; i++)
            {
                phraseMatch[i] = -1;
            }
            int matchesCount = 0;
            int lastIndex = -1;
            for (int i = 0; i < phrase.Length; i++)
            {
                string word = phrase[i];
                if (d.ContainsKey(word))
                {
                    var l = d[word];
                    bool found = false;
                    for (int j = 0; j < l.Count; j++)
                    {
                        if (l[j] > lastIndex)
                        {
                            lastIndex = l[j];
                            phraseMatch[i] = lastIndex;
                            matchesCount++;
                            found = true;
                            break;
                        }
                    }
                    if (found == false)
                    {
                        break;
                    }
                }
                else
                {
                    break;
                }
            }
            if (matchesCount == phrase.Length)
            {
                Console.WriteLine("YES");

                PrintMatches(phrase, phraseMatch);

                Console.WriteLine(LevenshteinDistance(t, p));
            }
            else
            {
                Console.WriteLine("NO");
                if (matchesCount == 0)
                {
                    Console.WriteLine("0");
                }
                else
                {
                    PrintMatches(phrase, phraseMatch);
                }
                Console.WriteLine("0");
            }
    }
    static int LevenshteinDistance(string s, string t)
        {
            if (s == t) return 0;
            if (s.Length == 0) return t.Length;
            if (t.Length == 0) return s.Length;

            int[] v0 = new int[t.Length + 1];
            int[] v1 = new int[t.Length + 1];

            for (int i = 0; i < v0.Length; i++)
                v0[i] = i;

            for (int i = 0; i < s.Length; i++)
            {
                v1[0] = i + 1;

                for (int j = 0; j < t.Length; j++)
                {
                    var cost = (s[i] == t[j]) ? 0 : 2;
                    v1[j + 1] = Math.Min(v1[j] + 1, Math.Min(v0[j + 1] + 1, v0[j] + cost));
                }

                for (int j = 0; j < v0.Length; j++)
                    v0[j] = v1[j];
            }

            return v1[t.Length];
        }

        static void PrintMatches(string[] phrase, int[] phraseMatch)
        {
            bool first = true;
            for (int i = 0; i < phraseMatch.Length; i++)
            {
                if (phraseMatch[i] >= 0)
                {
                    Console.Write("{0}{1} {2} {3}", first ? "" : " ", phrase[i], phraseMatch[i],
                        phraseMatch[i] + phrase[i].Length - 1);

                    first = false;
                }
            }
            Console.WriteLine();
        }
}