PHP排序二叉树基本功能实现方法示例

// created by 曲朋维// 排序二叉树// 完成以下任务.// 1. 将节点插入到对应位置// 2. 使用中序遍历遍历这个二叉树// 3. 找到这个二叉树的极值// 4. 搜索一个特定的值class Node{  public $key,$left,$right;  public function __construct($key)  {    $this->key = $key;  }}class BinaryTree{  public $root;  public $sortArr = [];  // 插入节点  public function insertNode($node,$newNode){    if ($node->key < $newNode->key){      // 如果父节点小于子节点,插到右边      if (empty($node->right)){        $node->right = $newNode;      }else{        $this->insertNode($node->right,$newNode);      }    }elseif ($node->key > $newNode->key){      // 如果父节点大于子节点,插到左边      if (empty($node->left)){        $node->left = $newNode;      }else{        $this->insertNode($node->left,$newNode);      }    }  }  public function insert($key){    $newNode = new Node($key);    if (empty($this->root)){      $this->root = $newNode;    }else{      $this->insertNode($this->root,$newNode);    }  }  // 中序遍历  public function midSort(){    $this->midSortNode($this->root);  }  public function midSortNode($node){    if (!empty($node)){      $this->midSortNode($node->left);      array_push($this->sortArr,$node->key);      $this->midSortNode($node->right);    }  }  // 寻找极值  public function findMin(){    //不断的找它的左子树,直到这个左子树的节点为叶子节点.    if (!empty($this->root)){      $this->findMinNode($this->root);    }  }  public function findMinNode(Node $node){    if (!empty($node->left)){      $this->findMinNode($node->left);    }else{      echo '这个二叉树的最小值为:'.$node->key;    }  }  public function findMax(){    if (!empty($this->root)){      $this->findMaxNode($this->root);    }  }  public function findMaxNode(Node $node){    if (!empty($node->right)){      $this->findMaxNode($node->right);    }else{      echo '这个二叉树的最大值为:'.$node->key;    }  }  // 查找特定的值  public function find($val = ''){    if (!empty($val)){      $this->findNode($this->root,$val);    }  }  public function findNode(Node $node,$val){    if ($node->key == $val){      echo '找到'.$val.'了';    }else if ($node->key > $val){      // 如果 父节点的值 大于要查找的值,那么查找它的左子树      if (!empty($node->left)){        $this->findNode($node->left,$val);      }else{        echo '没有这个东西!';      }    }else if ($node->key < $val){      if (!empty($node->right)){        $this->findNode($node->right,$val);      }else{        echo '没有这个东西!';      }    }  }}$tree = new BinaryTree();// 节点插入$nodes = array(8,3,10,1,6,14,4,7,13);foreach ($nodes as $value){  $tree->insert($value);}// 中序遍历//$tree->midSort();//print_r($tree->sortArr);// 寻找极值//$tree->findMin();//$tree->findMax();// 查找特定的值$tree->find(7);echo "<br/>";$tree->find(11);