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php实现的二叉树遍历算法示例

2017年06月28日 PHP博文 暂无评论

本文实例讲述了php实现的二叉树遍历算法。分享给大家供大家参考,具体如下:

今天使用php来实现二叉树的遍历

创建的二叉树如下图所示

php实现的二叉树遍历算法示例

php代码如下所示:

<?phpclass Node {  public $value;  public $child_left;  public $child_right;}final class Ergodic {  //前序遍历:先访问根节点,再遍历左子树,最后遍历右子树;并且在遍历左右子树时,仍需先遍历根节点,然后访问左子树,最后遍历右子树  public static function preOrder($root){    $stack = array();    array_push($stack, $root);    while(!empty($stack)){      $center_node = array_pop($stack);      echo $center_node->value . ' ';      //先把右子树节点入栈,以确保左子树节点先出栈      if($center_node->child_right != null) array_push($stack, $center_node->child_right);      if($center_node->child_left != null) array_push($stack, $center_node->child_left);    }  }  //中序遍历:先遍历左子树、然后访问根节点,最后遍历右子树;并且在遍历左右子树的时候。仍然是先遍历左子树,然后访问根节点,最后遍历右子树  public static function midOrder($root){    $stack = array();    $center_node = $root;    while (!empty($stack) || $center_node != null) {      while ($center_node != null) {        array_push($stack, $center_node);        $center_node = $center_node->child_left;      }      $center_node = array_pop($stack);      echo $center_node->value . ' ';      $center_node = $center_node->child_right;    }  }  //后序遍历:先遍历左子树,然后遍历右子树,最后访问根节点;同样,在遍历左右子树的时候同样要先遍历左子树,然后遍历右子树,最后访问根节点  public static function endOrder($root){    $push_stack = array();    $visit_stack = array();    array_push($push_stack, $root);    while (!empty($push_stack)) {      $center_node = array_pop($push_stack);      array_push($visit_stack, $center_node);      //左子树节点先入$pushstack的栈,确保在$visitstack中先出栈      if ($center_node->child_left != null) array_push($push_stack, $center_node->child_left);      if ($center_node->child_right != null) array_push($push_stack, $center_node->child_right);    }    while (!empty($visit_stack)) {      $center_node = array_pop($visit_stack);      echo $center_node->value . ' ';    }  }}//创建二叉树$a = new Node();$b = new Node();$c = new Node();$d = new Node();$e = new Node();$f = new Node();$g = new Node();$h = new Node();$i = new Node();$a->value = 'http://www.jb51.net/article/A';$b->value = 'http://www.jb51.net/article/B';$c->value = 'http://www.jb51.net/article/C';$d->value = 'http://www.jb51.net/article/D';$e->value = 'http://www.jb51.net/article/E';$f->value = 'http://www.jb51.net/article/F';$g->value = 'http://www.jb51.net/article/G';$h->value = 'http://www.jb51.net/article/H';$i->value = 'http://www.jb51.net/article/I';$a->child_left = $b;$a->child_right = $c;$b->child_left = $d;$b->child_right = $g;$c->child_left = $e;$c->child_right = $f;$d->child_left = $h;$d->child_right = $i;//前序遍历Ergodic::preOrder($a); //结果是:A B D H I G C E Fecho '<br/>';//中序遍历Ergodic::midOrder($a); //结果是: H D I B G A E C Fecho '<br/>';//后序遍历Ergodic::endOrder($a); //结果是: H I D G B E F C A

更多关于PHP相关内容感兴趣的读者可查看本站专题:《PHP数据结构与算法教程》、《PHP基本语法入门教程》、《php面向对象程序设计入门教程》、《php字符串(string)用法总结》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》

希望本文所述对大家PHP程序设计有所帮助。

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