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数据结构与算法(C#实现)系列---树

 Heavenkiller(原创)

首先我们给树下一个定义:

树是一个有限的、非空的结点集,

T={r} or T1 or T2 or…or Tn

它具有下列性质:

1.集合指定的结点r叫做树的根结点

2.其余的结点可以划分成n个子集,T1,T2,…Tn(n>=0),其中每一个子集都是一棵树。

 

树的其它定义如度,叶子,高等就请大家查阅别的资料吧,到处都有的。

 

树的主要性质一个就是遍历,分为深度遍历和广度遍历

在这里分别实现为DepthFirstTravesal()和WidthFirstTravesal()

其中深度遍历又分为前序遍历、中序遍历、和后序遍历

这是是采用适配器技术实现的。

 

using System;

using System.Collections;

 

namespace DataStructure

{

     /// <summary>

     /// Tree 的摘要说明。

     /// when traverse, traversaltype can't be changed,or throw a  exception

     /// 支持枚举、比较、深度复制

     /// </summary>

     public abstract class Tree:IEnumerable,IComparable

     {

         public Tree()

         {

              //

              // TODO: 在此处添加构造函数逻辑

              //

         }

         protected Queue keyqueue=new Queue();//仅仅用于枚举时存放数据,不参与Equals实现中的比较

         protected TraversalType traversaltype=TraversalType.Breadth;// choose a traversal  type,and  DepthFirst is default

         //protected uint degree=0;//degree of the tree, init  it as 0

         //protected uint height=0;//height of the tree, init it as 0

 

         //枚举不同的遍历类型

         public enum TraversalType

         {

              Breadth=1,//广度遍历

              PreDepth=2,//前序遍历

              InDepth=3,//中序遍历

              PostDepth=4//后序遍历

             

         };

         //public virtual abstract object  Key{}

        

         public abstract Tree this[uint _index]{get;set;}//if I only use get, can I change it later?

 

         public  abstract object Key{get;}

         public  abstract uint Degree{get;}

         //public  abstract uint Height{get;}

         public  void SetTraversalType(TraversalType _type){traversaltype=_type;}//set a traversal a type, if it's not set manually, DepthFirst will be chosen in default

 

         public  abstract bool IsEmpty();// property takes the place of IsEmpty()

         public  abstract bool IsLeaf();

        

         //Only Visit, needn't queue

         public virtual void DepthFirstTraversal(IPrePostVisitor _vis)//middle depthfirst traversal

         {

              //通过_vis使用不同的访问者来进行前序、后序、中序遍历

        

        

              if(!IsEmpty())

              {

                   _vis.PreVisit(this.Key);

 

                   if( this.Degree>=1 )

                   {

                       if( this.Degree>=2)

                       {

                            for(uint i=0;i<(this.Degree-1);i++)//

                            {

                                 this[i].DepthFirstTraversal(_vis);//recursive call

                                 //_vis.Visit(this.Key);

                            }

                       }

                       this[this.Degree-1].DepthFirstTraversal(_vis);

                   }

 

                   _vis.PostVisit(this.Key);

              }

             

             

         }

        

         public virtual void BreadthFirstTraversal(IVisitor _vis)//breadth first traversal

         {

              Queue tmpQueue=new Queue();//used to help BreadthFirstTraversal

              //this.keyqueue=new Queue();//store keys

 

              if(!this.IsEmpty())

                   tmpQueue.Enqueue(this);//enqueue the root node at first

              while(tmpQueue.Count!=0)//until the number of the queue is zero

              {

                   Tree headTree=(Tree)tmpQueue.Dequeue();

                   //this.keyqueue.Enqueue(headTree.Key);

                   _vis.Visit(headTree.Key);

                  

                   for(uint i=0;i<headTree.Degree;i++)

                   {

                       Tree childTree=headTree[i];

                       if(!childTree.IsEmpty())

                            tmpQueue.Enqueue(childTree);

                   }

              }

 

         }

        

         //------------------------------------------------end------------------------------------

         //内部成员类 用于提供不同遍历类型的访问者

         public class PreOrder:IPrePostVisitor

         {

              private IVisitor visitor;

              public PreOrder(IVisitor _vis){visitor=_vis;}

              #region IPrePostVisitor 成员

 

              public void PreVisit(object _obj)

              {

                   // TODO:  添加 PreOrder.PreVisit 实现

                   this.visitor.Visit(_obj);

              }

 

              public void Visit(object _obj)

              {

                   // TODO:  添加 PreOrder.Visit 实现

              }

 

              public void PostVisit(object _obj)

              {

                   // TODO:  添加 PreOrder.PostVisitor 实现

              }

 

              #endregion

 

         }
数据结构与算法(C#实现)系列---树(二)

                    Heavenkiller(原创)

 

         public class InOrder:IPrePostVisitor

         {

              private IVisitor visitor;

              public InOrder(IVisitor _vis){visitor=_vis;}

              #region IPrePostVisitor 成员

 

              public void PreVisit(object _obj)

              {

                   // TODO:  添加 InOrder.PreVisit 实现

              }

 

              public void Visit(object _obj)

              {

                   // TODO:  添加 InOrder.Visit 实现

                   this.visitor.Visit(_obj);

              }

 

              public void PostVisit(object _obj)

              {

                   // TODO:  添加 InOrder.PostVisitor 实现

              }

 

              #endregion

 

          }

         public class PostOrder:IPrePostVisitor

         {

              private IVisitor visitor;

              public PostOrder(IVisitor _vis){visitor=_vis;}

              #region IPrePostVisitor 成员

 

              public void PreVisit(object _obj)

              {

                   // TODO:  添加 PostOrder.PreVisit 实现

              }

 

              public void Visit(object _obj)

              {

                   // TODO:  添加 PostOrder.Visit 实现

              }

 

              public void PostVisit(object _obj)

              {

                   // TODO:  添加 PostOrder.PostVisitor 实现

                   this.visitor.Visit(_obj);

              }

 

              #endregion

 

         }

         protected class EnumVisitor:IVisitor

         {

              Queue thisQueue;

              public EnumVisitor(Queue _que)

              {

                   this.thisQueue=_que;

              }

              #region IVisitor 成员

 

              public void Visit(object _obj)

              {

                   // TODO:  添加 EnumVisitor.Visit 实现

                   this.thisQueue.Enqueue(_obj);

              }

 

              #endregion

         }

 

 

 

 

         #region IEnumerable 成员

 

         public IEnumerator GetEnumerator()

         {

              // TODO:  添加 Tree.GetEnumerator 实现

              EnumVisitor vis=new EnumVisitor(this.keyqueue);

              switch (this.traversaltype)

              {

                   case TraversalType.Breadth:

                       BreadthFirstTraversal(vis);

                        break;

                   case TraversalType.PreDepth:

                       PreOrder preVis=new PreOrder(vis);

                       DepthFirstTraversal(preVis);                      

                       break;

                   case TraversalType.InDepth:

                       InOrder inVis=new InOrder(vis);

                       DepthFirstTraversal(inVis);                   

                       break;

                  case TraversalType.PostDepth:

                       PostOrder postVis=new PostOrder(vis);

                       DepthFirstTraversal(postVis);                     

                       break;

             

                   default:

                       Console.WriteLine("WARNING:please set a travel type first!--void SetTraversalType(TraversalType _type) ");

                       //throw new Exception("WARNING:please set a travel type first!");//if not set a type, a exception will happen

                       break;

              }

              return this.keyqueue.GetEnumerator();

         }

 

         #endregion

数据结构与算法(C#实现)系列---树(三)

 Heavenkiller(原创)

 

         //overwrite Object.Equals() ---  reference  type   realization

         public override bool Equals(object _obj)

         {

              if( _obj==null )

                   return false;//因为this不可能为null

              if( ! (this.GetType()==_obj.GetType()) )

                   return false;//类型不相等也不相等

              Tree tmpObj=(Tree)_obj;

              //比较引用成员

              if( !Object.Equals(this.Key,tmpObj.Key) )

                   return false;

             

              //比较值类型成员

              if( !this.Degree.Equals(tmpObj.Degree) )

                   return false;

              //if( !this.Height.Equals(tmpObj.Height) )

                   //return false;

 

              return true;

         }

         //在此重载 ==,!= 后, 在以后继承的类中不必实现了

         public static bool operator==(Tree _treeA,Tree _treeB)

         {

              return Object.Equals(_treeA,_treeB);

         }

         public static bool operator!=(Tree _treeA,Tree _treeB)

         {

              return !(_treeA==_treeB);

         }

        

 

    

 

    

    

         #region IComparable 成员

 

         public virtual int CompareTo(object obj)

         {

              // TODO:  添加 Tree.CompareTo 实现

              return 0;

         }

 

         #endregion

    

     }

}

posted on 2005-11-23 16:40 卓如 阅读(...) 评论(...) 编辑 收藏