refactor: rewrite arrayqueue

datastructure/queue/arrayqueue.go

@@ -1,79 +1,101 @@
 package datastructure
 
 import (
-	"errors"
 	"fmt"
 	"reflect"
 )
 
 // ArrayQueue implements queue with slice
 type ArrayQueue[T any] struct {
-	data   []T
-	length int
+	items    []T
+	head     int
+	tail     int
+	capacity int
+	size     int
 }
 
-// NewArrayQueue return a empty ArrayQueue pointer
-func NewArrayQueue[T any](values ...T) *ArrayQueue[T] {
-	data := make([]T, len(values))
-	for i, v := range values {
-		data[i] = v
+func NewArrayQueue[T any](capacity int) *ArrayQueue[T] {
+	return &ArrayQueue[T]{
+		items:    make([]T, 0, capacity),
+		head:     0,
+		tail:     0,
+		capacity: capacity,
+		size:     0,
 	}
-	return &ArrayQueue[T]{data: data, length: len(values)}
 }
 
 // Data return queue data
 func (q *ArrayQueue[T]) Data() []T {
-	return q.data
+	items := []T{}
+	for i := q.head; i < q.tail; i++ {
+		items = append(items, q.items[i])
+	}
+	return items
 }
 
 // Size return length of queue data
 func (q *ArrayQueue[T]) Size() int {
-	return q.length
+	return q.size
 }
 
 // IsEmpty checks if queue is empty or not
 func (q *ArrayQueue[T]) IsEmpty() bool {
-	return q.length == 0
+	return q.size == 0
 }
 
 // Front return front value of queue
 func (q *ArrayQueue[T]) Front() T {
-	return q.data[0]
+	return q.items[0]
 }
 
 // Back return back value of queue
 func (q *ArrayQueue[T]) Back() T {
-	return q.data[q.length-1]
+	return q.items[q.size-1]
 }
 
 // EnQueue put element into queue
-func (q *ArrayQueue[T]) EnQueue(value T) {
-	q.data = append(q.data, value)
-	q.length++
+func (q *ArrayQueue[T]) Enqueue(item T) bool {
+	if q.head == 0 && q.tail == q.capacity {
+		return false
+	} else if q.head != 0 && q.tail == q.capacity {
+		for i := q.head; i < q.tail; i++ {
+			q.items[i-q.head] = q.items[i]
+		}
+		q.tail = q.tail - q.head
+		q.head = 0
+	}
+
+	q.items = append(q.items, item)
+	q.tail++
+	q.size++
+	return true
 }
 
 // DeQueue remove head element of queue and return it, if queue is empty, return nil and error
-func (q *ArrayQueue[T]) DeQueue() (*T, error) {
-	if q.IsEmpty() {
-		return nil, errors.New("queue is empty")
+func (q *ArrayQueue[T]) Dequeue() (T, bool) {
+	var item T
+	if q.head == q.tail {
+		return item, false
 	}
-
-	headItem := q.data[0]
-	q.data = q.data[1:]
-	q.length--
-
-	return &headItem, nil
+	item = q.items[q.head]
+	q.head++
+	q.size--
+	return item, true
 }
 
 // Clear the queue data
 func (q *ArrayQueue[T]) Clear() {
-	q.data = []T{}
-	q.length = 0
+	capacity := q.capacity
+	q.items = make([]T, 0, capacity)
+	q.head = 0
+	q.tail = 0
+	q.size = 0
+	q.capacity = capacity
 }
 
 // Contain checks if the value is in queue or not
 func (q *ArrayQueue[T]) Contain(value T) bool {
-	for _, v := range q.data {
+	for _, v := range q.items {
 		if reflect.DeepEqual(v, value) {
 			return true
 		}
@@ -84,8 +106,8 @@ func (q *ArrayQueue[T]) Contain(value T) bool {
 // Print queue data
 func (q *ArrayQueue[T]) Print() {
 	info := "["
-	for _, v := range q.data {
-		info += fmt.Sprintf("%+v, ", v)
+	for i := q.head; i < q.tail; i++ {
+		info += fmt.Sprintf("%+v, ", q.items[i])
 	}
 	info += "]"
 	fmt.Println(info)