private void RemoveNode(LinkedNode toRemove)
{
// remove current one and relink
var prev = toRemove.Prev;
var next = toRemove.Next;
prev.Next = next;
next.Prev = prev;
}
private void MoveToHead(LinkedNode first)
{
// move to head
var second = Head.Next;
Head.Next = first;
first.Prev = Head;
first.Next = second;
second.Prev = first;
}
public void Put(int key, int value)
{
if (Dictionary.TryGetValue(key, out var node))
{
RemoveNode(node);
MoveToHead(node);
node.Val = value;
}
else
{
if (Dictionary.Count == Capacity)
{
var last = Tail.Prev;
RemoveNode(last);
Dictionary.Remove(last.Key);
}
var newNode = new LinkedNode {
Key = key, Val = value
};
MoveToHead(newNode);
Dictionary[key] = newNode;
}
}