Beispiel #1
0
        private static void Main()
        {
            var inputString   = Console.ReadLine();
            var decodingTable = new Dictionary <char, bool[]>();
            var huffmanTree   = new TreeRoot();

            Encode(inputString, ref decodingTable, ref huffmanTree);
            Console.WriteLine($"Input String: {inputString}\n\nTree:");
            PrintTree(huffmanTree);
            Console.WriteLine("\nDecoding Table:");
            PrintDecodingTable(decodingTable);
        }
Beispiel #2
0
        public static void Encode(string input,
                                  ref Dictionary <char, bool[]> decodingTable,
                                  ref TreeRoot tree)
        {
            // build priority queue
            var priorityQueue = new PriorityQueue <TreeNode>();
            // first item in tuple is count, second is priority
            var chars = new Dictionary <char, (int, int)>();

            foreach (var c in input)
            {
                if (chars.ContainsKey(c))
                {
                    chars[c] = (chars[c].Item1 + 1, chars[c].Item2 + 1);
                }
                else
                {
                    chars[c] = (1, 1);
                }
            }

            // conflicts :P
            while (chars.Any(p => chars.Count(o => o.Value == p.Value) > 1))
            {
                foreach (var(c, p) in chars)
                {
                    if (chars.Count(o => o.Value.Item2 == p.Item2) > 1)
                    {
                        chars[c] = (chars[c].Item1, chars[c].Item2 + 1);
                    }
                }
            }

            foreach (var(c, i) in chars)
            {
                priorityQueue.Enqueue((input.Length - i.Item2) * 2,
                                      new TreeNode
                {
                    Character = c,
                    Count     = i.Item1
                });
            }

            // convert flat queue into tree
            while (priorityQueue.Count > 1)
            {
                var low1 = priorityQueue.Dequeue();
                var low2 = priorityQueue.Dequeue();
                var node = new TreeNode
                {
                    Left  = low1,
                    Right = low2,
                    Count = low1.Count + low2.Count
                };

                priorityQueue.Enqueue(input.Length * input.Length - (low1.Count + low2.Count), node);
            }

            // extract tree
            tree = (TreeRoot)priorityQueue.Dequeue();

            // build decoding table
            var route = new List <bool>();

            EncodeTraverseTree(tree, ref decodingTable, ref route);
        }
Beispiel #3
0
 private static void PrintTree(TreeRoot root)
 {
     ((TreeNode)root).Left?.PrintTree("");
     // ReSharper disable once TailRecursiveCall
     ((TreeNode)root).Right?.PrintTree("", true);
 }