/// <summary>
/// 链表结点
/// </summary>
class Node
{
  //结点数据，前后结点
  public object Data;
  public Node PreviousNode;
  public Node NextNode;
  //构造函数
  public Node(object data = null)
  {
    Data = data;
    PreviousNode = null;
    NextNode = null;
  }
  //输出结点信息
  public override string ToString()
  {
    return Data.ToString();
  }
}
/// <summary>
/// 链表类
/// </summary>
class MyLinkedList
{
  //首结点、尾结点
  public Node First;
  public Node Last;
  //下一个结点、上一个结点
  public Node NextNode(Node n) { return n.NextNode; }
  public Node PreviousNode(Node n) { return n.PreviousNode; }
  //结点总数
  public int Count;
  //构造函数
  public MyLinkedList()
  {
    this.First = null;
    this.Last = null;
    Count = 0;
  }
  /// <summary>
  /// 在结点node1之后增加结点node2，如果没有该结点则在最后增加
  /// </summary>
  /// <param name=\"node1\">结点1</param>
  /// <param name=\"node2\">结点2</param>
  public void AddAfter(Node node1, Node node2)
  {
    //链表为空的情况
    if (First == null)
    {
      Console.WriteLine(\"Linked-list is null! Can not find node1(\" + node1 + \")\");
      return;
    }
    Node temp = First;
    do
    {
      if (temp.Data.Equals(node1.Data))
      {
        //如果node1是尾结点
        if (node1.NextNode == null)
        {
          node2.NextNode = null;
          node2.PreviousNode = node1;
          node1.NextNode = node2;
        }
        else //如果node1不是尾结点
        {
          node2.NextNode = node1.NextNode;
          node2.PreviousNode = node1;
          node2.NextNode.PreviousNode = node2;
          node1.NextNode = node2; ;
        }
        Count++;
        Console.WriteLine(\"Node(\" + node2 + \"): Add Complete!\");
        return;
      }
      temp = temp.NextNode;
    }
    while (temp != null);
    Console.WriteLine(\"Can not find node(\" + node1 + \"), Misson defeat\");
  }
  /// <summary>
  /// 在链表尾部增加结点
  /// </summary>
  public void AddLast(Node node)
  {
    //链表为空的情况
    if (this.First == null) 
    {
      node.NextNode = null;
      node.PreviousNode = null;
      this.First = node;
      this.Last = node;
    }
    else //链表不为空的情况
    {
      Node temp = First;
      while(temp.NextNode != null)
      {
        temp = temp.NextNode;
      }
      temp.NextNode = node;
      node.PreviousNode = temp;
      Last = node;
    }
    Count++;
    Console.WriteLine(\"Node(\" + node + \"): Add Complete!\");
  }
  /// <summary>
  /// 删除指定结点
  /// </summary>
  /// <param name=\"node\">被删除结点</param>
  public void Delete(Node node)
  {
    if (Count == 0)
    {
      Console.WriteLine(\"Can not find node(\" + node + \")\");
      return;
    }
    Node temp = First;
    do
    {
      //如果数据部分匹配，则删去该结点
      if (temp.Data.Equals(node.Data))
      {
        //temp是尾结点
        if (temp.NextNode == null)
        {
          temp.PreviousNode.NextNode = null;
          temp = null;
        }
        else //temp不是尾结点 
        {
          temp.PreviousNode.NextNode = temp.NextNode;
          temp.NextNode.PreviousNode = temp.PreviousNode;
          temp = null;
        }
        Count--;
        Console.WriteLine(\"Node(\" + node + \"): Delete Complete!\");
        return;
      }
      temp = temp.NextNode;
    }
    while (temp != null);
    Console.WriteLine(\"Can not find node(\" + node + \"), Misson defeat\");
  }
  /// <summary>
  /// 修改结点值
  /// </summary>
  /// <param name=\"node\">被修改结点</param>
  /// <param name=\"value\">结点值</param>
  public void Modify(Node node, object value)
  {
    if (Count == 0)
    {
      Console.WriteLine(\"Can not find node(\" + node + \")\");
      return;
    }
    Node temp = First;
    do
    {
      if (temp.Data.Equals(node.Data))
      {
        Console.WriteLine(\"Node: \" + temp.Data + \" → \" + value.ToString());
        temp.Data = value;
        return;
      }
      temp = temp.NextNode;
    }
    while (temp != null);
  }
  /// <summary>
  /// 打印链表
  /// </summary>
  public void Print()
  {
    if (First == null)
    {
      Console.WriteLine(\"No nodes in this linked-list.\");
      return;
    }
    else
    {
      Console.WriteLine(\"Print the linked-list...\");
      Node temp = First;
      do
      {
        Console.WriteLine(temp.ToString());
        temp = temp.NextNode;
      }
      while (temp != null);
      Console.WriteLine(\"Mission Complete!\");
    }
  }
}

static void Main(string[] args)
{
  MyLinkedList ll = new MyLinkedList();
  //添加三个结点 1 2（在1后） 3（在2后）
  Node n1 = new Node(\"node1\");      
  Node n2 = new Node(\"node2\");
  Node n3 = new Node(\"node3\");
  ll.AddLast(n1);
  ll.AddLast(n2);
  ll.AddLast(n3);
  //添加三个结点 1.5（在1后） 2.5（在2后） 3.5（在3后）
  Node n1dot5 = new Node(\"node1dot5\");
  Node n2dot5 = new Node(\"node2dot5\");
  Node n3dot5 = new Node(\"node3dot5\");
  ll.AddAfter(n1, n1dot5);
  ll.AddAfter(n2, n2dot5);
  ll.AddAfter(n3, n3dot5);
  Console.WriteLine(\"========================\");
  //打印链表
  ll.Print();
  Console.WriteLine(\"========================\");
  //删除结点 2 和 3，将结点 2.5 的值改为 \"ThisNodeIsModified!\"
  ll.Delete(n2);
  ll.Delete(n3);
  ll.Modify(n2dot5, \"ThisNodeIsModified!\");
  Console.WriteLine(\"========================\");
  //打印链表
  ll.Print();
  Console.ReadLine();
}