设计一个求结点x在二叉树中的双亲结点算法，c++实现

以下是C++实现的求结点x在二叉树中的双亲结点算法：

//定义二叉树结点
struct TreeNode {
    char value;
    TreeNode* LeftChild;    TreeNode* RightChild;
    TreeNode* parent;
};

//递归查找结点x的双亲结点
TreeNode* findParent(TreeNode* root, TreeNode* x) {
    if (root == NULL || root == x) {
        return NULL;
    }
    if (root->LeftChild == x || root->RightChild == x) {
        return root;
    }
    TreeNode* left = findParent(root->LeftChild, x);
    if (left != NULL) {
        return left;
    }
    return findParent(root->RightChild, x);
}

//非递归查找结点x的双亲结点
TreeNode* findParent(TreeNode* root, TreeNode* x) {
    if (root == NULL || root == x) {
        return NULL;
    }
    stack<TreeNode*> s;
    s.push(root);
    while (!s.empty()) {
        TreeNode* node = s.top();
        s.pop();
        if (node->LeftChild == x || node->RightChild == x) {
            return node;
        }
        if (node->RightChild != NULL) {
            s.push(node->RightChild);
        }
        if (node->LeftChild != NULL) {
            s.push(node->LeftChild);
        }
    }
    return NULL;
}