从主树中获取子树php

<?php

// 定义树节点类
class TreeNode {
    public $value;
    public $children;

    public function __construct($value) {
        $this->value = $value;
        $this->children = array();
    }

    public function addChild($child) {
        $this->children[] = $child;
    }
}

// 递归函数，用于从主树中获取子树
function getSubtree($node, $targetValue) {
    // 如果当前节点的值等于目标值，则返回当前节点作为子树
    if ($node->value == $targetValue) {
        return $node;
    }

    // 遍历当前节点的子节点
    foreach ($node->children as $child) {
        // 递归调用获取子树的函数
        $subtree = getSubtree($child, $targetValue);
        // 如果找到了目标子树，则返回该子树
        if ($subtree != null) {
            return $subtree;
        }
    }

    // 如果当前节点及其子节点都不包含目标值，则返回空
    return null;
}

// 创建一个示例树
$root = new TreeNode("A");
$nodeB = new TreeNode("B");
$nodeC = new TreeNode("C");
$nodeD = new TreeNode("D");
$nodeE = new TreeNode("E");
$nodeF = new TreeNode("F");

$root->addChild($nodeB);
$root->addChild($nodeC);
$nodeB->addChild($nodeD);
$nodeB->addChild($nodeE);
$nodeC->addChild($nodeF);

// 从主树中获取子树
$subtree = getSubtree($root, "B");

// 打印子树的值
if ($subtree != null) {
    echo "子树的值为：" . $subtree->value;
} else {
    echo "未找到目标子树";
}

?>