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doubly-linked-list.go
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doubly-linked-list.go
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package datastructures
type DoublyLinkedListNode struct {
Data interface{}
Next *DoublyLinkedListNode
Previous *DoublyLinkedListNode
}
type DoublyLinkedList struct {
head *DoublyLinkedListNode
tail *DoublyLinkedListNode
length int
}
// NewDoublyLinkedList returns a new doubly linked list.
func NewDoublyLinkedList() *DoublyLinkedList {
return &DoublyLinkedList{}
}
// Add adds a new node to the tail doubly linked list.
func (l *DoublyLinkedList) Add(node *DoublyLinkedListNode) *DoublyLinkedList {
if l.IsEmpty() {
l.head = node
l.tail = node
l.length++
return l
}
node.Previous = l.tail
l.tail.Next = node
l.tail = node
l.length++
return l
}
// AddHead adds a new node to the head of the doubly linked list.
func (l *DoublyLinkedList) AddHead(node *DoublyLinkedListNode) *DoublyLinkedList {
if l.IsEmpty() {
l.head = node
l.tail = node
l.length++
return l
}
node.Next = l.head
l.head.Previous = node
l.head = node
l.length++
return l
}
// AddTail adds a new node to the tail of the linked list.
func (l *DoublyLinkedList) AddTail(node *DoublyLinkedListNode) *DoublyLinkedList {
if l.IsEmpty() {
l.head = node
l.tail = node
l.length++
return l
}
node.Previous = l.tail
l.tail.Next = node
l.tail = node
l.length++
return l
}
// Clear clears all the values from the linked list.
func (l *DoublyLinkedList) Clear() {
if l.IsEmpty() {
return
}
trav := l.head
for trav != nil {
next := trav.Next
trav.Next = nil
trav.Previous = nil
trav = next
}
l.length = 0
}
// Iterate iterates through the doubly linked list and executes the callback function
// f for each iteration.
//
// TODO(wisdommatt): include iterator with Stop method in the f callback function
// parameters. The reason for this is to stop the iteration if the remaining items
// are not needed.
func (l *DoublyLinkedList) Iterate(f func(index int, node *DoublyLinkedListNode)) {
trav := l.head
index := 0
for trav != nil {
next := trav.Next
f(index, trav)
trav = next
index++
}
}
// Size retrieves the size of the list.
func (l DoublyLinkedList) Size() int {
return l.length
}
// IsEmpty returns true if the list is empty else false.
func (l DoublyLinkedList) IsEmpty() bool {
return l.length == 0
}
// GetHead returns the head of the list.
func (l *DoublyLinkedList) GetHead() *DoublyLinkedListNode {
return l.head
}
// GetTail returns the tail of the list.
func (l *DoublyLinkedList) GetTail() *DoublyLinkedListNode {
return l.tail
}
// RemoveHead removes a node from the head of the doubly linked list.
func (l *DoublyLinkedList) RemoveHead() *DoublyLinkedList {
if l.IsEmpty() {
return l
}
if l.Size() == 1 {
l.head = nil
l.tail = nil
l.length--
return l
}
l.head = l.head.Next
l.length--
return l
}
// RemoveTail removes a node from the tail of the doubly linked list.
func (l *DoublyLinkedList) RemoveTail() *DoublyLinkedList {
if l.IsEmpty() {
return l
}
if l.Size() == 1 {
l.head = nil
l.tail = nil
l.length--
return l
}
l.tail = l.tail.Previous
l.length--
return l
}