63 lines
1.4 KiB
PHP
63 lines
1.4 KiB
PHP
<?php
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/**
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* File: TreeNode.php
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* Created Time: 2024-05-19
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* Author: DoWake (admin@mengxing.cc)
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*/
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/* 二叉树节点类 */
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class TreeNode
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{
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public $val; // 节点值
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public $height; // 节点高度
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public $left; // 左子节点引用
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public $right; // 右子节点引用
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/* 构造方法 */
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public function __construct($val = 0, $left = null, $right = null, $height = 0)
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{
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$this->val = $val;
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$this->left = $left;
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$this->right = $right;
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$this->height = $height;
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}
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/* 将列表反序列化为二叉树：递归 */
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private static function listToTreeDFS($arr, $i = 0)
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{
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if ($i < 0 || $i >= count($arr) || $arr[$i] === null) {
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return null;
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}
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$root = new TreeNode($arr[$i]);
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$root->left = self::listToTreeDFS($arr, 2 * $i + 1);
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$root->right = self::listToTreeDFS($arr, 2 * $i + 2);
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return $root;
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}
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/* 将列表反序列化为二叉树 */
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public static function listToTree($arr)
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{
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return self::listToTreeDFS($arr, 0);
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}
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/* 将二叉树序列化为列表：递归 */
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private static function treeToListDFS($root, $i, &$res)
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{
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if ($root === null) {
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return;
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}
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$res[$i] = $root->val;
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self::treeToListDFS($root->left, 2 * $i + 1, $res);
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self::treeToListDFS($root->right, 2 * $i + 2, $res);
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}
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/* 将二叉树序列化为列表 */
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public static function treeToList($root)
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{
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$res = [];
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self::treeToListDFS($root, 0, $res);
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return $res;
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}
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}
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