PHP implementation of the clues two-fork tree and Binary tree traversal method detailed _php skills

This article describes the PHP implementation of the clue two-fork tree and Binary tree traversal method. Share to everyone for your reference, specific as follows:

<?php
  require ' bitree.php ';
  $str = ' ko#be8#tr### #acy ##### ';
  $tree = new Bitree ($STR);
  $tree->createthreadtree ();
  echo $tree->threadlist (). "\ n"; two-fork Tree
  Echo $tree->threadlistreserv () starting at the first node, and traversing?> from the last node.

bitree.php:

? /** * PHP Implementation two fork tree * * @author Zhaojiangwei * @since 2011/10/25 10:32///node class node{private $dat
    A = NULL;
    Private $left = NULL;
    Private $right = NULL;
    Private $lTag = 0;
    Private $rTag = 0;
    Public Function Node ($data = False) {$this->data = $data;
    //I don't like using magic method Public Function GetData () {return $this->data;
    The Public Function SetData ($data) {$this->data = $data;
    The Public Function GetLeft () {return $this->left;
    The Public Function Setleft ($left) {$this->left = $left;
    The Public Function GetRight () {return $this->right;
    The Public Function Setright ($right) {$this->right = $right;
    The Public Function Getltag () {return $this->ltag;
    The Public Function Setltag ($tag) {$this->ltag = $tag;
    The Public Function Getrtag () {return $this->rtag; The Public Function Setrtag ($tag) {$thIs->rtag = $tag;
    }//Clue two fork tree class bitree{Private $datas = null;//string to import; Private $root = NULL; root node Private $leafCount = number of 0;//leaf nodes private $headNode = NULL; Clue two fork tree head node Private $preNode = null;//traversal of a threaded binary tree saves the previous Traversal node public function Bitree ($datas) {Is_array ($datas) | |
      $datas = Str_split ($datas);
      $this->datas = $datas;
      $this->backupdata = $this->datas;
    $this->createtree (TRUE); //Pre-sequence traversal create tree//$root determine if you want to create a root node public function createtree ($root = FALSE) {if emptyempty ($this->datas
      ) return NULL;
      $first = Array_shift ($this->datas);
      if ($first = = ' # ') {return NULL;
        }else{$node = new node ($first);
        $root && $this->root = $node;
        $node->setleft ($this->createtree ());
        $node->setright ($this->createtree ());
      return $node; }//Returns the number of tree leaf nodes public Function getleafcount () {$this->figurEleafcount ($this->root);
    return $this->leafcount;
      The Private Function Figureleafcount ($node) {if ($node = = NULL) return false;
      if ($this->checkempty ($node)) {$this->leafcount + +;
        }else{$this->figureleafcount ($node->getleft ());
      $this->figureleafcount ($node->getright ()); }//Judgment node is not a leaf node private function checkempty ($node) {if ($node->getleft () = = NULL && $node-&G
      T;getright () = = NULL) {return true;
    return false;
    //Returns the binary tree depth public function getdepth () {return $this->traversdepth ($this->root);
      }//Traversal binary tree depth public function traversdepth ($node) {if ($node = = NULL) {return 0;
      $u = $this->traversdepth ($node->getleft ()) + 1;
      $v = $this->traversdepth ($node->getright ()) + 1; return $u > $v?
    $u: $v; //Returns the traversal result, in the form of a string//$order returned in the form of traversal, the front and back public functioN getlist ($order = ' front ') {if ($this->root = null) return null;
      $nodeList = Array ();
          Switch ($order) {case "front": $this->frontlist ($this->root, $nodeList);
        Break
          Case "Middle": $this->middlelist ($this->root, $nodeList);
        Break
          Case "Last": $this->lastlist ($this->root, $nodeList);
        Break
          Default: $this->frontlist ($this->root, $nodeList);
      Break
    Return implode ($nodeList);
      //Create a Clue two fork tree public Function Createthreadtree () {$this->headnode = new Node ();
      $this->prenode = & $this->headnode;
      $this->headnode->setltag (0);
      $this->headnode->setleft ($this->root);
      $this->headnode->setrtag (1);
      $this->threadtraverse ($this->root);
      $this->prenode->setright ($this->headnode);
      $this->prenode->setrtag (1); $this->heAdnode->setright ($this->prenode); }//threaded binary tree Private function Threadtraverse ($node) {if ($node!= null) {if ($node->getleft () = null
          ) {$node->setltag (1);
        $node->setleft ($this->prenode);
        }else{$this->threadtraverse ($node->getleft ()); } if ($this->prenode!= $this->headnode && $this->prenode->getright () = NULL) {$this
          ->prenode->setrtag (1);
        $this->prenode->setright ($node);
      $this->prenode = & $node//note refers to $this->threadtraverse ($node->getright ());
      }//From the first node traverse the middle order clue two fork tree public Function threadlist () {$arr = array (); for ($node = $this->getfirstthreadnode ($this->root) $node!= $this->headnode; $node = $this->getnextnode ($
      node) {$arr [] = $node->getdata ();
    Return implode ($arr); ///reverse-traverse middle order thread from tail node two-fork tree public Function threadlistrEserv () {$arr = array ();
        for ($node = $this->headnode->getright (); $node!= $this->headnode; $node = $this->getprenode ($node)) {
      $arr [] = $node->getdata ();
    Return implode ($arr); //Returns the precursor public function Getprenode ($node) {if ($node->getltag () = 1) {return $node->getl of a node.
      EFT ();
      }else{return $this->getlastthreadnode ($node->getleft ()); }//Returns a node's successor public function Getnextnode ($node) {if ($node->getrtag () = 1) {return $node-&
      Gt;getright ();
      }else{return $this->getfirstthreadnode ($node->getright ());
        }//Returns the first node of the two-fork tree in the order clue Public function Getfirstthreadnode ($node) {while ($node->getltag () = = 0) {
      $node = $node->getleft ();
    return $node; //Returns the last node of the middle order clue two fork tree public Function Getlastthreadnode ($node) {while ($node->getrtag () = = 0) {$nod
  E = $node->getright ();    return $node; }//forward traversal private function frontlist ($node, & $nodeList) {if ($node!== NULL) {$nodeList [] = $node
        ->getdata ();
        $this->frontlist ($node->getleft (), $nodeList);
      $this->frontlist ($node->getright (), $nodeList); The In//sequence traverses private function middlelist ($node, & $nodeList) {if ($node!= NULL) {$this->mid
        Dlelist ($node->getleft (), $nodeList);
        $nodeList [] = $node->getdata ();
      $this->middlelist ($node->getright (), $nodeList); }//Sequence traversal private function lastlist ($node, & $nodeList) {if ($node!= NULL) {$this->lastl
        IST ($node->getleft (), $nodeList);
        $this->lastlist ($node->getright (), $nodeList);
      $nodeList [] = $node->getdata ();
    The Public Function GetData () {return $this->data;
    The Public Function Getroot () {return $this->root;

 }}?>

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