//Returns the value of the specified key in O(1) time..
public int Get(int key)
{
if (dict.ContainsKey(key))
{
DoubleLinkedListNode node = dict[key];
RemoveNode(node);
InsertNode(node);
return(node.val);
}
return(-1);
}
//Adds or updates the key in the cache in O(1) time.
public void Put(int key, int value)
{
if (dict.ContainsKey(key))
{
RemoveNode(dict[key]);
}
DoubleLinkedListNode nodeToAdd = new DoubleLinkedListNode(key, value);
if (dict.Count == _capacity)
{
//If capacity is full, remove the node just before the dummy last node.
RemoveNode(dummyLastNode.prev);
}
InsertNode(nodeToAdd);
}