[数据结构]——二叉搜索树与双向链表

输入一棵二叉搜索树，将该二叉搜索树转换成一个排序的双向链表。要求不能创建任何新的结点，只能调整树中结点指针的指向

    TreeNode* prev = NULL;
    void _Convert(TreeNode* cur)
    {
        if(cur == NULL) return;
        _Convert(cur->left);
        cur->left = prev;
        if(prev)
        prev->right = cur;
        prev = cur;
        _Convert(cur->right);
    }
    
    TreeNode* Convert(TreeNode* pRootOfTree)
    {
        if(pRootOfTree == NULL) return NULL;
        
        _Convert(pRootOfTree);
        TreeNode* head = pRootOfTree;
        while(head && head->left)
        {
            head = head -> left;
        }
        return head;
    }