Data structures and algorithms (C # implementation) series --- tree (1)

Data structures and algorithms (C # implementation) series --- tree (1)

Heavenkiller (original)

First, let's define the tree:

A tree is a finite, non-empty node set,

T = {r} or T1 or T2 or... Or Tn

It has the following properties:

1. the node r specified in the set is called the root node of the tree.

2. The remaining nodes can be divided into n subsets, T1, T2 ,... Tn (n> = 0), where each subset is a tree.

 

Other tree definitions, such as degree, leaf, and higher, are available everywhere.

 

One of the main features of a tree is traversal, which can be divided into deep traversal and breadth traversal.

Here, DepthFirstTravesal () and WidthFirstTravesal () are implemented respectively ()

Deep traversal is divided into pre-order traversal, middle-order traversal, and post-order traversal.

This is achieved by using the adapter technology.

 

Using System;

Using System. Collections;

 

Namespace DataStructure

{

/// <Summary>

/// Tree summary.

/// When traverse, traversaltype cant be changed, or throw a exception

/// Supports enumeration, comparison, and deep Replication

/// </Summary>

Public abstract class Tree: IEnumerable, IComparable

{

Public Tree ()

{

//

// TODO: add the constructor logic here

//

}

Protected Queue keyqueue = new Queue (); // It is used only for data storage during enumeration and is not used for comparison in Equals implementation.

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

 

// Enumerate different traversal types

Public enum TraversalType

{

Breadth = 1, // span Traversal

PreDepth = 2, // pre-order traversal

InDepth = 3, // traverse in the middle order

PostDepth = 4 // post-order traversal

};

// 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 its 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, neednt queue

Public virtual void DepthFirstTraversal (IPrePostVisitor _ vis) // middle depthfirst traversal

{

// Use different visitors through _ vis to perform forward, backward, and central Traversal

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 );

}