public void AddCache(int key, int val)
{
CacheNode node = new CacheNode(key, val);
node.Next = head.Next;
node.Prev = head;
head.Next = node;
if (node.Next != null)
node.Next.Prev = node;
if (tail == head)
{
tail = head.Next;
}
map.Add(key, node);
if (map.Count > maxCacheSize)
{
map.Remove(tail.Key);
tail = tail.Prev;
tail.Next = null;
}
}
public LRUCache(int size)
{
tail = head;
maxCacheSize = size;
}
public CacheNode()
{
Value = Key = 0;
Next = Prev = null;
}
public CacheNode(int key, int val)
{
Next = Prev = null;
Value = val;
Key = key;
}
public CacheNode GetCache(int key)
{
if (map.ContainsKey(key))
{
CacheNode node = map[key];
// If node is already the first one in the list, nothing need to be done
if (node != head.Next)
{
if (tail == node)
{
tail = node.Prev;
tail.Next = null;
}
else
{
node.Prev.Next = node.Next;
node.Next.Prev = node.Prev;
}
head.Next.Prev = node;
node.Next = head.Next;
node.Prev = head;
head.Next = node;
}
return node;
}
return null;
}