PHP排序二叉樹基本功能實現(xiàn)方法示例

// created by 曲朋維
// 排序二叉樹
// 完成以下任務.
// 1. 將節(jié)點插入到對應位置
// 2. 使用中序遍歷遍歷這個二叉樹
// 3. 找到這個二叉樹的極值
// 4. 搜索一個特定的值
class Node{
  public $key,$left,$right;
  public function __construct($key)
  {
    $this->key = $key;
  }
}
class BinaryTree{
  public $root;
  public $sortArr = [];
  // 插入節(jié)點
  public function insertNode($node,$newNode){
    if ($node->key  $newNode->key){
      // 如果父節(jié)點小于子節(jié)點,插到右邊
      if (empty($node->right)){
        $node->right = $newNode;
      }else{
        $this->insertNode($node->right,$newNode);
      }
    }elseif ($node->key > $newNode->key){
      // 如果父節(jié)點大于子節(jié)點,插到左邊
      if (empty($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);
    }
  }
  // 中序遍歷
  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);
    }
  }
  // 尋找極值
  public function findMin(){
    //不斷的找它的左子樹,直到這個左子樹的節(jié)點為葉子節(jié)點.
    if (!empty($this->root)){
      $this->findMinNode($this->root);
    }
  }
  public function findMinNode(Node $node){
    if (!empty($node->left)){
      $this->findMinNode($node->left);
    }else{
      echo '這個二叉樹的最小值為:'.$node->key;
    }
  }
  public function findMax(){
    if (!empty($this->root)){
      $this->findMaxNode($this->root);
    }
  }
  public function findMaxNode(Node $node){
    if (!empty($node->right)){
      $this->findMaxNode($node->right);
    }else{
      echo '這個二叉樹的最大值為:'.$node->key;
    }
  }
  // 查找特定的值
  public function find($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 > $val){
      // 如果 父節(jié)點的值 大于要查找的值,那么查找它的左子樹
      if (!empty($node->left)){
        $this->findNode($node->left,$val);
      }else{
        echo '沒有這個東西!';
      }
    }else if ($node->key  $val){
      if (!empty($node->right)){
        $this->findNode($node->right,$val);
      }else{
        echo '沒有這個東西!';
      }
    }
  }
}
$tree = new BinaryTree();
// 節(jié)點插入
$nodes = array(8,3,10,1,6,14,4,7,13);
foreach ($nodes as $value){
  $tree->insert($value);
}
// 中序遍歷
//$tree->midSort();
//print_r($tree->sortArr);
// 尋找極值
//$tree->findMin();
//$tree->findMax();
// 查找特定的值
$tree->find(7);
echo "br/>";
$tree->find(11);