arazmj / gerdu

package dlinklist

// Node data structure

type Node struct {

	next  *Node

	prev  *Node

	Key   string

	Value string

	Freq  int

}

// DLinkedList data structure

type DLinkedList struct {

	head *Node

	tail *Node

	size int

}

// NewLinkedList constructor

func NewLinkedList() *DLinkedList {

	head := &Node{}

	tail := &Node{}

	head.next = tail

	tail.prev = head

	return &DLinkedList{

		head: head,

		tail: tail,

	}

}

// AddNode adds a new node to the tail of of linked list

func (c *DLinkedList) AddNode(node *Node) {

	next := c.head.next

	c.head.next = node

	next.prev = node

	node.next = next

	node.prev = c.head

	c.size++

}

// RemoveNode removes a node

func (c *DLinkedList) RemoveNode(node *Node) {

	prev := node.prev

	next := node.next

	prev.next = next

	next.prev = prev

	c.size--

}

// PopTail pops a node from the beginning of the linked list

func (c *DLinkedList) PopTail() *Node {

	prev := c.tail.prev

	c.RemoveNode(prev)

	return prev

}