AIKD

//FETCHER.CS

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace Alg_Huffmana
{
    class Fetcher
    {
        public static List<KeyValuePair<char, int>> FillDictionary(string path)
        {
            var charDictionary = new Dictionary<char, int>();
            using (StreamReader sr = File.OpenText(path))
            {
                while(!sr.EndOfStream)
                {
                    var ch = (char)sr.Read();
                    var item = charDictionary.Where(p => p.Key == ch);
                    if (item.Count() != 0)
                    {
                        var itemValue = charDictionary[ch];
                        charDictionary[ch] = ++itemValue;
                    }
                    else
                    {
                        charDictionary.Add(ch, 1);
                    }
                }
            }
            var sortedList = charDictionary.ToList();
            sortedList.Sort((p1, p2) => p1.Value.CompareTo(p2.Value));
            SortedDictionary<char, int> sortedDictionary = new SortedDictionary<char, int>(charDictionary);
            sortedDictionary.OrderBy(p => p.Value);
            return sortedList;
        }
    }
}

//Huffman.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NGenerics.DataStructures.Trees;

namespace Alg_Huffmana
{

    public class HuffmanTree : BinaryTree<Node>
    {
        private KeyValuePair<int, int> root;
        public void Add(int key, int value)
        {
            if (this.Count == 0)
            {
                root = new KeyValuePair<int, int>(key, value);
            }
        }

        public string GetCodeFromTree(KeyValuePair<char, int> pair) //PRZESZUKIWANIE
        {

        }
    }
}


//Node.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Alg_Huffmana
{
    public class Node
    {
        public int sumLeftRight { get; set; }
        public KeyValuePair<char, int> pair { get; set; }

        public int Compare(object x, object y)
        {
            if (((Node)x).pair.Value > ((Node)y).pair.Value)
            {
                return 1;
            }

            if (((Node)x).pair.Value < ((Node)y).pair.Value)
            {
                return -1;
            }
            else
            {
                return 0;
            }
        }
    }
}

Nuget NGenerics BinnaryTree