C# 数据结构与算法系列(三) 线性表之链表

线性表的链存储称为链表。特点：存储单元上非连续、非顺序的存储结构，数据元素的逻辑顺序是通过链表中的指针链接次序实现的。
链表由一系列结点（链表中每一个元素称为结点）组成，结点可以在运行时动态生成。每个结点包括两个部分：一个是存储数据元素
的数据域，另一个是存储下一个结点地址的指针域。
链表有单链表,双向链表等
下面介绍单链表的实现方法：

public class Node<T>
{
private T data;
private Node<T> next;

public Node(T val, Node<T> p)
{
data = val;
next = p;
}
public Node(Node<T> p)
{
next = p;
}
public Node(T val)
{
data = val;
}
public Node()
{
data = default(T);
next = null;
}
public T Data
{
get { return data; }
set { data = value; }
}
public Node<T> Next
{
get { return next; }
set { next = value; }
}
}

public class LinkList<T>
{
private Node<T> head;
public Node<T> Head
{
get { return head; }
set { head = value; }
}
public LinkList()
{
head = null;
}
public int GetLength()
{
Node<T> p = head;
int len = 0;
while (p != null)
{
++len;
p = p.Next;
}
return len;
}
public void clear()
{
head = null;
}
public bool isEmpty()
{
if (head == null)
return true;
else
return false;
}
public void Append(T item)
{
Node<T> q = new Node<T>(item);
Node<T> p = new Node<T>();
if (head == null)
{
head = q;
return;
}
p = head;
while (p.Next != null)
{
p = p.Next; //把位置定义在最后
}
p.Next = q; //添加元素
}
public void Insert(T item, int i)
{
if (isEmpty() || i < 1)
{
throw new Exception("Insert: Error!");
}
if (i == 1)
{
Node<T> q = new Node<T>(item);
q.Next = head;
head = q;
return;
}
Node<T> p = head;
Node<T> r = new Node<T>();
int j = 1;
while (p.Next != null && j < i)
{
r = p;
p = p.Next;
++j;
}
if (j == i)
{
Node<T> q = new Node<T>(item);
q.Next = p;
r.Next = q;
}
else
{
throw new Exception("Insert: Error");
}
}
public T Delete(int i)
{
if (isEmpty() && i < 0)
{
throw new Exception("Error");
}
Node<T> q = new Node<T>();
if (i == 1)
{
q = head;
head = head.Next;
return q.Data;
}
Node<T> p = head;
int j = 1;
while (p.Next != null && j < i)
{
++j;
q = p;
p = p.Next;
}
if (j == i)
{
q.Next = p.Next;
return p.Data;
}
else
{
return default(T);
}
}
public T GetElem(int i)
{
if (isEmpty())
{
return default(T);
}
Node<T> p = new Node<T>();
p = head;
int j = 1;
while (p.Next != null && j < i)
{
++j;
p = p.Next;
}
if (j == i)
{
return p.Data;
}
else
{
return default(T);
}
}
public int Locate(T value)
{
if (isEmpty())
{
return -1;
}
Node<T> p = new Node<T>();
p = head;
int i = 1;
while (!p.Data.Equals(value) && p.Next != null)
{
p = p.Next;
++i;
}
return i;
}
}

下面代码来使用链表

private void button1_Click(object sender, EventArgs e)
{
try
{
LinkList<string> str = new LinkList<string>();
str.Head = new Node<string> ("A");
str.Append("B");
str.Append("D");
str.Append("E");
str.Insert("C", 5);

richTextBox1.Text = str.GetElem(1) + str.GetElem(2) + str.GetElem(3) + str.GetElem(4) + str.GetElem(5);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}