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c#algorithmdata-structurestrie

How to create a trie in c#


Does anyone know where I can find an example of how to construct a trie in C#? I'm trying to take a dictionary/list of words and create a trie with it.


Solution

  • This is my own code, pulled from my answer to How to find a word from arrays of characters? :

    public class Trie
    {
      public struct Letter
      {
        public const string Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        public static implicit operator Letter(char c)
        {
          return new Letter() { Index = Chars.IndexOf(c) };
        }
        public int Index;
        public char ToChar()
        {
          return Chars[Index];
        }
        public override string ToString()
        {
          return Chars[Index].ToString();
        }
      }
    
      public class Node
      {
        public string Word;
        public bool IsTerminal { get { return Word != null; } }
        public Dictionary<Letter, Node> Edges = new Dictionary<Letter, Node>();
      }
    
      public Node Root = new Node();
    
      public Trie(string[] words)
      {
        for (int w = 0; w < words.Length; w++)
        {
          var word = words[w];
          var node = Root;
          for (int len = 1; len <= word.Length; len++)
          {
            var letter = word[len - 1];
            Node next;
            if (!node.Edges.TryGetValue(letter, out next))
            {
              next = new Node();
              if (len == word.Length)
              {
                next.Word = word;
              }
              node.Edges.Add(letter, next);
            }
            node = next;
          }
        }
      }