private DLinkedDicNode PopTail()
{
DLinkedDicNode result = Tail.Previous;
RemoveNode(result);
return(result);
}
public LeetCode146(int capacity)
{
Capacity = capacity;
Size = 0;
Head = new DLinkedDicNode(0, 0);
Tail = new DLinkedDicNode(0, 0);
// initialed an double linked list
Head.Post = Tail;
Tail.Previous = Head;
}
private void AddNode(DLinkedDicNode node)
{
// The following process is add the node in between Head node and second node
// 1 <-> 5 now we want add 3
// 1 <- 3
node.Previous = Head;
// 1 <- 3 -> 5
node.Post = Head.Post;
// 1 <- 3 <->5
Head.Post.Previous = node;
// 1 <-> 3 <-> 5
Head.Post = node;
}
private void RemoveNode(DLinkedDicNode node)
{
// the following logic should be to remove a node in double list
// 1 <-> 3 <-> 5, we want remove 3
// temp1 temp2 temp1 holds previous element, temp2 holds post value
DLinkedDicNode temp1 = node.Previous;
DLinkedDicNode temp2 = node.Post;
// 1<- 3 <-> 5
// 1 ->5
temp1.Post = temp2;
// 1 <-> 5
temp2.Previous = temp1;
}
public override string ToString()
{
StringBuilder sb = new StringBuilder();
sb.Append("Hot[");
while (Head != null)
{
sb.Append($"{Head.Value},");
Head = Head.Post;
}
sb.Append("]Cold");
return(sb.ToString());
}
public void Put(int key, int value)
{
if (!cache.ContainsKey(key))
{
var newNode = new DLinkedDicNode(key, value);
AddNode(newNode);
cache.Add(key, newNode);
Size++;
if (Size > Capacity)
{
var temp = PopTail();
cache.Remove(temp.Key);
Size--;
}
}
else
{
cache[key].Value = value;
MoveToHead(cache[key]);
}
}
private void MoveToHead(DLinkedDicNode node)
{
RemoveNode(node);
AddNode(node);
}
