generic queue

fundamentals/queue/queue.go

@@ -1,37 +1,32 @@
 package queue
 
-// "Generic" item.
+type Queue[T any] interface {
-// When type parameters will land this type became
+	Enqueue(T)
-// type Item[T any] T
+	Dequeue() T
-type Item interface{}
-
-type Queue interface {
-	Enqueue(Item)
-	Dequeue() Item
 	Size() int
 	IsEmpty() bool
 }
 
 // We use linked list as internal data structure
 // to get O(1) speed for push and pop opeartions
-type node struct {
+type node[Item any] struct {
 	item Item
-	next *node
+	next *node[Item]
 }
 
-type queue struct {
+type queue[OfType any] struct {
 	size int
-	head *node
+	head *node[OfType]
-	tail *node
+	tail *node[OfType]
 }
 
-func NewQueue() Queue {
+func NewQueue[OfType any]() Queue[OfType] {
-	return &queue{}
+	return &queue[OfType]{}
 }
 
-func (q *queue) Enqueue(item Item) {
+func (q *queue[T]) Enqueue(item T) {
 	oldTail := q.tail
-	q.tail = &node{item: item, next: nil}
+	q.tail = &node[T]{item: item, next: nil}
 	if q.IsEmpty() {
 		q.head = q.tail
 	} else {
@@ -40,7 +35,7 @@ func (q *queue) Enqueue(item Item) {
 	q.size++
 }
 
-func (q *queue) Dequeue() Item {
+func (q *queue[T]) Dequeue() T {
 	first := q.head
 	q.head = q.head.next
 	if q.IsEmpty() {
@@ -50,10 +45,10 @@ func (q *queue) Dequeue() Item {
 	return first.item
 }
 
-func (q *queue) Size() int {
+func (q *queue[T]) Size() int {
 	return q.size
 }
 
-func (q *queue) IsEmpty() bool {
+func (q *queue[T]) IsEmpty() bool {
 	return q.head == nil
 }

fundamentals/queue/queue_test.go

@@ -6,13 +6,13 @@ import (
 )
 
 func TestSimple(t *testing.T) {
-	queue := NewQueue()
+	queue := NewQueue[int]()
 
 	queue.Enqueue(10)
 	queue.Enqueue(20)
 	queue.Enqueue(30)
 
-	first, second := queue.Dequeue().(int), queue.Dequeue().(int)
+	first, second := queue.Dequeue(), queue.Dequeue()
 
 	if first != 10 && second != 20 {
 		log.Fatal("wrong order")
@@ -20,7 +20,7 @@ func TestSimple(t *testing.T) {
 }
 
 func TestSize(t *testing.T) {
-	queue := NewQueue()
+	queue := NewQueue[int]()
 
 	if queue.Size() != 0 {
 		log.Fatal("empty queue should have size 0")

go.mod

@@ -1,3 +1,3 @@
 module github.com/fotonmoton/algorithms
 
-go 1.16
+go 1.18