哈夫曼编码 C#

我是从《数据结构与算法 C#语言描述》这本书里面抄的 ， 程序可以正常运行

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace 哈夫曼编码1{    public class HuffmanTree    {        private HuffmanTree lChild;        private HuffmanTree rChild;        private string letter;        private int freq;        public HuffmanTree(string letter)        {            this.letter = letter;            this.freq = 1;        }        public HuffmanTree LChild        {            get { return lChild; }            set { lChild = value; }        }        public HuffmanTree RChild        {            get { return rChild; }            set { rChild = value; }        }        public string Letter        {            get { return letter; }            set { letter = value; }        }        public int Freq        {            get { return freq; }            set { freq = value; }        }        public void IncFreq()        {            freq++;        }    }}

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace 哈夫曼编码1{    public class Node    {        public HuffmanTree data;        public Node link;        public Node(HuffmanTree newData)        {            data = newData;        }    }}

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace 哈夫曼编码1{    public class TreeList    {        private int count = 0;        private Node first = null;        private static string[] signTable = null;        private static string[] keyTable = null;        public TreeList(string input)        {            List<char> list = new List<char>();            for (int i = 0; i < input.Length; i++)            {                if (!list.Contains(input[i]))                {                    list.Add(input[i]);    //如果不包含string里的字符，就加上去                }            }            signTable = new string[list.Count];            keyTable = new string[list.Count];        }        public string[] GetSignTable()        {            return signTable;        }        public string[] GetKeyTable()        {            return keyTable;        }        public void AddLetter(string letter)        {            HuffmanTree hTemp = new HuffmanTree(letter);            Node eTemp = new Node(hTemp);            if (first == null)            {                first = eTemp;            }            else            {                eTemp.link = first;                first = eTemp;            }            count++;        }        public void SortTree()        {            if (first != null && first.link != null)            {                Node tmp1;                Node tmp2;                for (tmp1 = first; tmp1 != null; tmp1 = tmp1.link)                {                    for (tmp2 = tmp1.link; tmp2 != null; tmp2 = tmp2.link)                    {                        if (tmp1.data.Freq > tmp2.data.Freq)                        {                            HuffmanTree tmpHT = tmp1.data;                            tmp1.data = tmp2.data;                            tmp2.data = tmpHT;                        }                    }                }//按照权重（freq）升序排列            }        }        /// <summary>        /// 去掉结点        /// </summary>        /// <returns>去掉的结点</returns>        public HuffmanTree RemoveTree()        {            if (first != null)            {                HuffmanTree hTmp;                hTmp = first.data;                first = first.link;                count--;                return hTmp;            }            return null;        }        /// <summary>        /// 插入结点        /// </summary>        /// <param name="hTmp">等待插入的结点</param>        public void InsertTree(HuffmanTree hTmp)        {            Node eTmp = new Node(hTmp);            if (first == null)            {                first = eTmp;            }            else            {                Node p = first;                while (p.link != null)                {                    if (p.data.Freq <= hTmp.Freq                        && p.link.data.Freq >= hTmp.Freq)                    {                        break;                    }                    p = p.link;                }                eTmp.link = p.link;                p.link = eTmp;            }            count++;        }        /// <summary>        /// 合并成一棵树        /// </summary>        public void MergeTree()        {            if (first != null)            {                if (first.link != null)                {                    HuffmanTree aTmp = RemoveTree();                    HuffmanTree bTmp = RemoveTree();                    HuffmanTree sumTmp = new HuffmanTree("x");                    sumTmp.LChild = aTmp;                    sumTmp.RChild = bTmp;                    sumTmp.Freq = aTmp.Freq + bTmp.Freq;                    InsertTree(sumTmp);                }            }        }        public int Lenght()        {            return count;        }        /// <summary>        /// 增加字符        /// </summary>        /// <param name="str">等待增加的字符</param>        public void AddSign(string str)        {            if (first == null)            {                AddLetter(str);                return;            }            Node tmp = first;            while (tmp != null)            {                if (tmp.data.Letter == str)                {                    tmp.data.IncFreq();                    return;                }                tmp = tmp.link;            }            AddLetter(str);        }        static public string Translate(string original)        {            string newStr = "";            for (int i = 0; i < original.Length; i++)            {                for (int j = 0; j < signTable.Length; j++)                {                    if (original[i].ToString() == signTable[j])                    {                        newStr += keyTable[j];                    }                }            }            return newStr;        }        static int pos = 0;        static public void MakeKey(HuffmanTree tree, string code)        {            if (tree.LChild == null)            {                signTable[pos] = tree.Letter;                keyTable[pos] = code;                pos++;            }            else            {                MakeKey(tree.LChild, code + "0");                MakeKey(tree.RChild, code + "1");            }        }    }}

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace 哈夫曼编码1{    class Program    {        static void Main(string[] args)        {            string input;            Console.Write("Enter a string to encode :  ");            input = Console.ReadLine();            TreeList treeList = new TreeList(input);            for (int i = 0; i < input.Length; i++)            {                treeList.AddSign(input[i].ToString());            }            treeList.SortTree();            while (treeList.Lenght() > 1)            {                treeList.MergeTree();            }            TreeList.MakeKey(treeList.RemoveTree(), "");            string newStr = TreeList.Translate(input);            string[] signTable = treeList.GetSignTable();            string[] keyTable = treeList.GetKeyTable();            for (int i = 0; i < signTable.Length; i++)            {                Console.WriteLine(signTable[i] + ": " + keyTable[i]);            }            Console.WriteLine("The original string is " + input.Length * 16 + "bits long . ");            Console.WriteLine("the new string is " + newStr.Length + "bits long  . ");            Console.WriteLine("The coded string looks like this : " + newStr);            Console.Read();        }    }}