/// <summary>
/// insert key and value into hashtable
/// if the key already in the hashtable, change the value
/// </summary>
/// <param name="key"></param>
/// <param name="val"></param>
public void Insert(K key, V val)
{
SingleListNode <K, V> results = search(key);
if (results != null)
{
results.Value = val;
return;
}
SingleListNode <K, V> node = new SingleListNode <K, V>(key, val);
node.Next = arrs[GetPosition(key)];
arrs[GetPosition(key)] = node;
count++;
if (count / arrs.Length >= 10)
{
SingleListNode <K, V>[] tmp = arrs;
arrs = new SingleListNode <K, V> [count];
count = 0;
for (int i = 0; i < tmp.Length; i++)
{
SingleListNode <K, V> sln = tmp[i];
while (sln != null)
{
Insert(sln.Key, sln.Value);
sln = sln.Next;
}
}
}
}
/// <summary>
/// search the key from table
/// If not found, return null
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
private SingleListNode <K, V> search(K key)
{
int position = GetPosition(key);
SingleListNode <K, V> results = arrs[position];
while (results != null && !results.Key.Equals(key))
{
results = results.Next;
}
return(results);
}
public void Insert(T item)
{
SingleListNode <T> node = new SingleListNode <T>(item);
Count++;
if (head == null || tail == null)
{
head = tail = node;
}
else
{
tail.Next = node;
}
}
/// <summary>
/// search
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
public SingleListNode <T> Search(T item)
{
SingleListNode <T> node = head;
while (node != null)
{
if (node.Key.CompareTo(item) == 0)
{
return(node);
}
else
{
node = node.Next;
}
}
return(null);
}
/// <summary>
/// delete key in hashtable, if not contains , throw exception
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public V Delete(K key)
{
if (!Contains(key))
{
throw new Exception("can not find key");
}
int position = GetPosition(key);
SingleListNode <K, V> results = arrs[position];
if (results.Key.Equals(key))
{
arrs[position] = results.Next;
}
else
{
SingleListNode <K, V> before = arrs[position];
while (results != null && !results.Key.Equals(key))
{
before = results;
results = results.Next;
}
before.Next = results.Next;
}
count--;
if (count >= 4 && arrs.Length / count > 8)
{
SingleListNode <K, V>[] tmp = arrs;
arrs = new SingleListNode <K, V> [count];
count = 0;
for (int i = 0; i < tmp.Length; i++)
{
SingleListNode <K, V> sln = tmp[i];
while (sln != null)
{
Insert(sln.Key, sln.Value);
sln = sln.Next;
}
}
}
return(results.Value);
}
/// <summary>
/// delete the first item meet in list
/// </summary>
/// <param name="item"></param>
public void Delete(T item)
{
if (IsEmpty)
{
return;
}
SingleListNode <T> node = head;
while (node != null)
{
if (node.Key.CompareTo(item) == 0)
{
//this node is head
if (tail == head)
{
tail = null;
}
head = head.Next;
Count--;
return;
}
else if (node.Next != null && node.Next.Key.CompareTo(item) == 0)
{
Count--;
if (tail == node.Next)
{
tail = node;
node.Next = null;
}
else
{
node.Next = node.Next.Next;
}
return;
}
else
{
node = node.Next;
}
}
}
/// <summary>
/// whether the Hashtable contains the key
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public bool Contains(K key)
{
SingleListNode <K, V> results = search(key);
return(results != null);
}
/// <summary>
/// search the key from table
/// If not found, return null
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public V Search(K key)
{
SingleListNode <K, V> results = search(key);
return(results == null ? null : results.Value);
}
