本文继续 《关于某道C#上机题的OO - 策略模式》中的题目，但这是使用的是双向循环链表。当第一次看到这题我首先想到的是循环链表，但题目要求面向对象的方法，汗~ 首先是双向链表
首先是双向链表的节点类
1 /// <summary>
2 /// 双向链表节点
3 /// </summary>
4 /// <typeparam name="T"></typeparam>
5 public class DoubleLinkNode<T>
6 {
7 public DoubleLinkNode() { }
8 public DoubleLinkNode(T item)
9 {
10 Value = item;
11 }
12 /// <summary>
13 /// 节点值
14 /// </summary>
15 public T Value { get; set; }
16 /// <summary>
17 /// 下一个节点
18 /// </summary>
19 public DoubleLinkNode<T> Next { get; set; }
20 /// <summary>
21 /// 前一个节点
22 /// </summary>
23 public DoubleLinkNode<T> Previous { get; set; }
24 public override string ToString()
25 {
26 return Value.ToString();
27 }
28 }这里使用的是泛型类，他的优势就不讨论了，下面是循环链表类
/// <summary>
/// 双向循环链表
/// </summary>
/// <typeparam name="T"></typeparam>
public class CircleList<T> : IEnumerable<T>
{
private int currentIndex;
private DoubleLinkNode<T> current;
/// <summary>
/// 头节点
/// </summary>
public DoubleLinkNode<T> First { get; private set; }
/// <summary>
/// 尾节点
/// </summary>
public DoubleLinkNode<T> Last { get; private set; }
/// <summary>
/// 节点数
/// </summary>
public int Count { get; private set; }
/// <summary>
/// 索引
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
public DoubleLinkNode<T> this[int index]
{
get
{
if (Count - index < index)
{
currentIndex = Count - 1;
current = Last;
while (currentIndex > 0)
{
if (currentIndex == index) break;
currentIndex--;
current = current.Previous;
}
}
else
{
Reset();
while (currentIndex < Count - 1)
{
if (currentIndex == index) break;
currentIndex++;
current = current.Next;
}
}
return current;
}
}
/// <summary>
/// 在尾部添加节点
/// </summary>
/// <param name="node"></param>
public void AddLast(DoubleLinkNode<T> node)
{
if (Last == null) Last = node;
if (First == null) First = node;
Last.Next = node;
node.Previous = Last;
Last = node;
node.Next = First;
First.Previous = node;
Count++;
Last.Next = First;
}
/// <summary>
/// 在尾部添加节点
/// </summary>
/// <param name="item"></param>
public void AddLast(T item)
{
DoubleLinkNode<T> node = new DoubleLinkNode<T>(item);
AddLast(node);
}
/// <summary>
/// 移除节点
/// </summary>
/// <param name="node"></param>
public void Remove(DoubleLinkNode<T> node)
{
node.Previous.Next = node.Next;
node.Next.Previous = node.Previous;
Count--;
}
/// <summary>
/// 移除节点
/// </summary>
/// <param name="item"></param>
public void Remove(T item)
{
DoubleLinkNode<T> node = Find(o => o.Value.Equals(item));
if (node == null) return;
Remove(node);
Count--;
}
/// <summary>
/// 查找节点
/// </summary>
/// <param name="match"></param>
/// <returns></returns>
public DoubleLinkNode<T> Find(Predicate<DoubleLinkNode<T>> match)
{
Reset();
while (currentIndex < Count)
{
if (match(current))
{
return current;
}
currentIndex++;
current = current.Next;
}
return null;
}
public IEnumerator<T> GetEnumerator()
{
Reset();
while (currentIndex < Count)
{
yield return current.Value;
current = current.Next;
currentIndex++;
}
}
IEnumerator IEnumerable.GetEnumerator()
{
return this.GetEnumerator();
}
public override string ToString()
{
string s = string.Empty;
Reset();
while (currentIndex < Count)
{
s += string.Format("Node:{0} NextNode:{1} PreviousNode:{2}\r\n", current, current.Next, current.Previous);
currentIndex++;
current = current.Next;
}
return s;
}
/// <summary>
/// 清除
/// </summary>
public void Clear()
{
Count = 0;
First = null;
Last = null;
}
private void Reset()
{
currentIndex = 0;
current = First;
}
}由于没用使用DoubleLinkNode<T>[] 来存储数据，所以索引的处理显得非常的麻烦（如果用了数组就存在链表的容量问题），希望高手们能给出好的方法。
下面就是具体实现了
class Program
{
static void Main(string[] args)
{
//初始化数据
CircleList<Person> list = new CircleList<Person>();
for (int i = 0; i < 17; i++)
{
list.AddLast(new Person(i + 1));
}
//当前报数人
DoubleLinkNode<Person> current = list.First;
//报数序号
int k = 0;
//循环报数
while (list.Count > 1)
{
k++;
Console.WriteLine(string.Format("{0}:{1}", current.Value.Id, k));
if (k % 3 == 0)
list.Remove(current);
current = current.Next;
}
Console.WriteLine(string.Format("Last Person:{0}", current.Value.Id));
Console.Read();
}
}
/// <summary>
/// 玩家
/// </summary>
public class Person
{
public Person(int id)
{
this.Id = id;
}
public int Id { get; set; }
}
下面是结果
