数据结构(C#)：单链表

与顺序表相比，链表有自己的特点：插入、删除操作无需移动元素；能够高效实现动态内存分配；但不能按节点索引快速定位到节点；由于需要记录指针域，系统开销较大。

本篇介绍单链表的实现，使用上一篇定义的接口。
代码：

/*
* File : SingleLinkedList.cs
* Author : Zhenxing Zhou
* Date : 2008-12-06
* Blog : http://www.xianfen.net/ */
using System;
using System.Collections;
using System.Collections.Generic;

namespace Xianfen.Net.DataStructure
{
// 定义节点
internal class SingleLinkedListNode<T>
{
private T m_Value;
private SingleLinkedListNode<T> m_Next;

public T Value
{
get { return m_Value; }
set { m_Value = value; }
}

public SingleLinkedListNode<T> Next
{
get { return m_Next; }
set { m_Next = value; }
}

public SingleLinkedListNode()
{
m_Next = null;
}

public SingleLinkedListNode(T t)
: this()
{
Value = t;
}
}

// 实现单链表
public class SingleLinkedList<T> : ILinearList<T>
{
private int m_Count;
private SingleLinkedListNode<T> m_Head;

public SingleLinkedList()
{
m_Count = 0;
m_Head = new SingleLinkedListNode<T>();
}

public SingleLinkedList(T t)
: this()
{
m_Count = 1;
m_Head.Next = new SingleLinkedListNode<T>(t);
}

public bool IsEmpty
{
get { return m_Count == 0; }
}

public int Count
{
get { return m_Count; }
}

public void Add(T t)
{
InsertAt(t, this.Count);
}

public void AddHead(T t)
{
InsertAt(t, 0);
}

public void AddTail(T t)
{
Add(t);
}

public void InsertAt(T t, int pos)
{
if (pos > this.Count || pos < 0)
{
throw new IndexOutOfRangeException("pos");
}

if (m_Count == int.MaxValue)
{
throw new ArithmeticException();
}

SingleLinkedListNode<T> currentNode = m_Head;

while (pos-- > 0)
{
currentNode = currentNode.Next;
}

SingleLinkedListNode<T> tempNode = new SingleLinkedListNode<T>(t);

tempNode.Next = currentNode.Next;
currentNode.Next = tempNode;
m_Count++;
}

public void RemoveTail()
{
RemoveAt(this.Count - 1);
}

public void RemoveHead()
{
RemoveAt(0);
}

public void RemoveAt(int pos)
{
if (pos >= Count || pos < 0)
{
throw new IndexOutOfRangeException("pos");
}

SingleLinkedListNode<T> currentNode = m_Head;

while (pos-- > 0)
{
currentNode = currentNode.Next;
}

currentNode.Next = currentNode.Next.Next;
m_Count--;
}

public void RemoveAll()
{
m_Head.Next = null;
m_Count = 0;
}

public void Clear()
{
RemoveAll();
}

public T GetHead()
{
return GetAt(0);
}

public T GetTail()
{
return GetAt(this.Count - 1);
}

public T GetAt(int pos)
{
return GetNodeAt(pos).Value;
}

private SingleLinkedListNode<T> GetNodeAt(int pos)
{
if (pos >= Count || pos < 0)
{
throw new IndexOutOfRangeException("pos");
}

SingleLinkedListNode<T> currentNode = m_Head;

while (pos-- > 0)
{
currentNode = currentNode.Next;
}

return currentNode.Next;
}

public void SetAt(int pos, T t)
{
GetNodeAt(pos).Value = t;
}

public int Find(T t)
{
SingleLinkedListNode<T> node = m_Head;
int pos = 0;

while ((node = node.Next) != null)
{
if (node.Value.Equals(t))
{
return pos;
}

pos++;
}

return -1;
}

public IEnumerator<T> GetEnumerator()
{
SingleLinkedListNode<T> node = m_Head;

while ((node = node.Next) != null)
{
yield return node.Value;
}
}

IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
}
}

如果发现BUG请留言指出，下一篇介绍双链表的实现。