Merge pull request wangzheng0822#270 from qqlcbb/master

完善24二叉树基本算法

Author: wangzheng0822

php/24_tree/Tree.php

@@ -0,0 +1,152 @@
+<?php
+
+namespace Algo_24;
+
+class Tree
+{
+
+ /**
+ * 树的根节点
+ * @var [type]
+ */
+ public $head = null;
+
+ /**
+ * [__construct description]
+ * @param TreeNode|null $head [description]
+ */
+ public function __construct($headData = null)
+ {
+ if ($headData != null) {
+ $this->head = new TreeNode($headData);
+ }
+ }
+
+ /**
+ * 查找数据
+ * @param [type] $data [数据]
+ * @return [type] [description]
+ */
+ public function find($data)
+ {
+ if ($this->head == null) {
+ return null;
+ }
+
+ $node = $this->head;
+
+ while ($node != null) {
+ if ($node->data == $data) {
+ return $node;
+ } elseif ($data > $node->data) {
+ $node = $node->right;
+ } else {
+ $node = $node->left;
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * 插入数据
+ * @param [type] $data [数据]
+ * @return [type] [description]
+ */
+ public function insert($data)
+ {
+ if ($this->head == null) {
+ $this->head = new TreeNode($data);
+ return true;
+ }
+
+ $node = $this->head;
+
+ while ($node != null) {
+ if ($data > $node->data) {
+ if ($node->right == null) {
+ $node->right = new TreeNode($data);
+ return true;
+ }
+ $node = $node->right;
+ } else {
+ if ($node->left == null) {
+ $node->left = new TreeNode($data);
+ return true;
+ }
+ $node = $node->left;
+ }
+ }
+ }
+
+ /**
+ * 删除节点
+ * @param [type] $data [节点]
+ * @return [type] [description]
+ */
+ public function delete($data)
+ {
+ // 找到需要删除节点
+ $node = $this->head;
+ $pnode = null;
+ while ($node != null) {
+ if ($node->data == $data) {
+ break;
+ } elseif ($data > $node->data) {
+ $pnode = $node;
+ $node = $node->right;
+ } else {
+ $pnode = $node;
+ $node = $node->left;
+ }
+ } 
+ if ($node == null) {
+ return false;
+ }
+ // 要删除的节点有两个子节点
+ // 查找右子树中最小节点
+ if ($node->left != null && $node->right != null) {
+ $minPP = $node;
+ $minP = $node->right;
+ while ($minP->left != null) {
+ $minPP = $minP;
+ $minP = $minP->left;
+ }
+ $node->data = $minP->data;
+ $node = $minP;
+ // 删除掉右子树中的最小节点
+ $minPP->left = null;
+ }
+
+ if ($node->left != null) {
+ $child = $node->left;
+ } elseif ($node->right != null) {
+ $child = $node->right;
+ } else {
+ $child = null;
+ }
+
+ if ($pnode == null) {
+ // 删除的是根节点
+ $node = $child;
+ } elseif ($pnode->left == $node) {
+ $pnode->left = $child;
+ } else {
+ $pnode->right = $child;
+ }
+ }
+
+ /**
+ * 前序遍历
+ * @return [type] [description]
+ */
+ public function preOrder($node)
+ {
+ if ($node == null) {
+ return ; 
+ }
+ echo $node->data . '->';
+ $this->preOrder($node->left);
+ $this->preOrder($node->right);
+ }
+}

php/24_tree/TreeNode.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Algo_24;
+
+class TreeNode
+{
+
+ /**
+ * 节点中的数据
+ * @var [type]
+ */
+ public $data;
+
+ /**
+ * 左节点
+ * @var [type]
+ */
+ public $left;
+
+ /**
+ * 右节点
+ * @var [type]
+ */
+ public $right;
+
+ /**
+ * [__construct description]
+ * @param [type] $data [description]
+ */
+ public function __construct($data = null)
+ {
+ $this->data = $data;
+ $this->left = null;
+ $this->right = null;
+ }
+}

php/24_tree/main.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Algo_24;
+
+require_once '../vendor/autoload.php';
+
+
+$tree = new Tree();
+
+$tree->insert(20);
+$tree->insert(30);
+$tree->insert(10);
+$tree->insert(21);
+$tree->insert(22);
+
+$tree->preOrder($tree->head);
+echo PHP_EOL;
+
+var_dump($tree->find(30));
+echo PHP_EOL;
+
+
+$tree->delete(30);
+$tree->preOrder($tree->head);
+echo PHP_EOL;

php/composer.json

@@ -8,7 +8,8 @@
  "Algo_06\\": "06_linkedlist/",
  "Algo_07\\": "07_linkedlist/",
  "Algo_08\\": "08_stack/",
- "Algo_09\\": "09_queue/"
+ "Algo_09\\": "09_queue/",
+ "Algo_24\\": "24_tree/"
  }
  }
 }