Tree structure customization and basic algorithms (Java Data Structure Learning notes)

The data structure can be classified into two types: linear structure and nonlinear structure, the content of this paper is about nonlinear structure: The basic definition of tree and its related algorithm. Some basic conceptual definitions of trees are available for reference: Wikipedia
ADT Model of the tree:
According to the tree definition, each node's descendants form a tree, called a subtree. Therefore, from the data type, the tree, subtree, tree nodes are equal status, can be seen as a node, using the Pass class: tree representation. As shown in the following:

Figure: Tree ADT Model
The "father-son-brother" model can be used to represent the ADT of the tree. , in addition to data items, with three references, respectively, to the father, son, brother, who points to the node.

Figure: Data structure of the "father-son-brother" model

Table: Actions implemented by the tree ADT

In the case of updates to the tree, different application issues require that the tree structure provide different methods. This difference is too large to define a generic update operation in the tree ADT. After that, we will combine various application problems, and give some specific update operation implementation.

Java interface for the tree:

 PackageCom.tree;/** * Java Structure for Tree * Construct Interface Tree * @author gannyee * */ Public  interface Tree {    //get size of tree which recent node as parent     Public int GetSize();//get height of recent node     Public int getheight();//get Depth of recent node     Public int getdepth();//get element of recent node     PublicObjectgetelement();//set element of recent node, return former element     PublicObjectsetElement(Object newelement);//get Parent of recent node     PublicTreelinkedlistgetParent();//get first child of recent node     PublicTreelinkedlistGetfirstchild();//get biggest sibling of recent node     PublicTreelinkedlistgetnextsibling();}

Java Code: tree node Model implementation

 PackageCom.tree;ImportJava.lang.reflect.Constructor; Public  class treelinkedlist implements Tree{    //pointer Point to Parent    PrivateTreelinkedlist parent;//element    PrivateObject element;//pointer point to FirstChild    PrivateTreelinkedlist FirstChild;//pointer point to NextSibling    PrivateTreelinkedlist nextSibling;//constructor     Public treelinkedlist(){ This(NULL,NULL,NULL,NULL); }//constructor with Parameters     Public treelinkedlist(Treelinkedlist p, Object e,treelinkedlist f,treelinkedlist N) { This. parent = P; This. element = e; This. FirstChild = f; This. nextSibling = n; }//get size of tree which recent node as parent     Public int GetSize(){intSize =1;//recent node also include own childrentreelinkedlist subtree = firstchild;//start with first child         while(NULL! = Subtree) {size + = Subtree.getsize (); subtree = subtree.getnextsibling ();//get all Descendants}returnSize }//get height of recent node     Public int getheight(){intHeight =-1;//recent node ' s (parent) Heighttreelinkedlist subtree = firstchild;//start with first child         while(NULL! = Subtree) {height = Math.max (height, subtree.getheight ());//get the max heightsubtree = subtree.getnextsibling (); }returnHeight +1;//get recent node height}//get Depth of recent node     Public int getdepth(){intdepth =0; Treelinkedlist p = parent;//start with parent         while(P! =NULL) {depth + +; p = p.getparent ();//get all parents of every node}returnDepth }//get element of recent node,if nothing return null     PublicObjectgetelement(){return  This. element; }//set element of recent Node,return former element     PublicObjectsetElement(Object newelement)        {Object swap; Swap = This. element; This. element = newelement;return  This. element; }//get Parent of recent node,if nothing return null     PublicTreelinkedlistgetParent(){returnParent }//get first child of recent node,if nothing return null     PublicTreelinkedlistGetfirstchild(){returnFirstChild; }//get biggest sibling of recent node,if nothing return null     PublicTreelinkedlistgetnextsibling(){returnnextSibling; }}

Test code:

Package com.tree; Public classtreetest {/** * @param args * *     Public Static void Main(string[] args) {//TODO auto-generated method stubTreelinkedlist A =NewTreelinkedlist (); Treelinkedlist B =NewTreelinkedlist (); Treelinkedlist C =NewTreelinkedlist (); Treelinkedlist d =NewTreelinkedlist (); Treelinkedlist e =NewTreelinkedlist (); Treelinkedlist f =NewTreelinkedlist (); Treelinkedlist g =NewTreelinkedlist (); A =NewTreelinkedlist (NULL,0DNULL); b =NewTreelinkedlist (A,1, D,c.getfirstchild ()); c =NewTreelinkedlist (A,2,NULL,NULL); D =NewTreelinkedlist (b,3, F,e.getfirstchild ()); E =NewTreelinkedlist (b,4,NULL,NULL); f =NewTreelinkedlist (D,5,NULL, G.getfirstchild ()); g =NewTreelinkedlist (D,6,NULL,NULL); System. out. println (A.getdepth ()); System. out. println (B.getdepth ()); System. out. println (C.getdepth ()); System. out. println (D.getdepth ()); System. out. println (E.getdepth ()); System. out. println (F.getdepth ()); System. out. println (A.getheight ()); System. out. println (B.getheight ()); System. out. println (C.getheight ()); System. out. println (D.getheight ()); System. out. println (E.getheight ()); System. out. println (F.getheight ()); System. out. println (G.getheight ()); }}

Test results:

012com.tree.TreeLinkedList@7c1c8c581nullnull

The following will give a tree traversal algorithm!

References: Data structures and Algorithms (Java description) Deng Junhui

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced. Personal GitHub code space: Https://github.com/gannyee

Tree structure customization and basic algorithm (Java Data Structure learning note)