feat: add CircularQueue

datastructure/queue/circularqueue.go

@@ -0,0 +1,119 @@
+package datastructure
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+// CircularQueue implements circular queue with slice,
+// last index of CircularQueue don't contain value, so acturl capacity is size - 1
+type CircularQueue[T any] struct {
+	data  []T
+	front int
+	rear  int
+	size  int
+}
+
+// NewCircularQueue return a empty CircularQueue pointer
+func NewCircularQueue[T any](size int) *CircularQueue[T] {
+	data := make([]T, size)
+	return &CircularQueue[T]{data: data, front: 0, rear: 0, size: size}
+}
+
+// Data return queue data
+func (q *CircularQueue[T]) Data() []T {
+	data := []T{}
+
+	front := q.front
+	rear := q.rear
+	if front <= rear {
+		return q.data[front:rear]
+	}
+
+	data = append(data, q.data[front:]...)
+	data = append(data, q.data[0:rear]...)
+
+	return data
+}
+
+// Length return current data length of queue
+func (q *CircularQueue[T]) Length() int {
+	if q.size == 0 {
+		return 0
+	}
+	return (q.rear - q.front + q.size) % q.size
+}
+
+// IsEmpty checks if queue is empty or not
+func (q *CircularQueue[T]) IsEmpty() bool {
+	return q.front == q.rear
+}
+
+// IsFull checks if queue is full or not
+func (q *CircularQueue[T]) IsFull() bool {
+	return (q.rear+1)%q.size == q.front
+}
+
+// Front return front value of queue
+func (q *CircularQueue[T]) Front() T {
+	return q.data[q.front]
+}
+
+// Back return back value of queue
+func (q *CircularQueue[T]) Back() T {
+	if q.rear-1 >= 0 {
+		return q.data[q.rear-1]
+	}
+	return q.data[q.size-1]
+}
+
+// EnQueue put element into queue
+func (q *CircularQueue[T]) EnQueue(value T) error {
+	if q.IsFull() {
+		return errors.New("queue is full!")
+	}
+
+	q.data[q.rear] = value
+	// q.data = append(q.data, value)
+	q.rear = (q.rear + 1) % q.size
+
+	return nil
+}
+
+// DeQueue remove head element of queue and return it, if queue is empty, return nil and error
+func (q *CircularQueue[T]) DeQueue() (*T, error) {
+	if q.IsEmpty() {
+		return nil, errors.New("queue is empty")
+	}
+
+	headItem := q.data[q.front]
+	var t T
+	q.data[q.front] = t
+	q.front = (q.front + 1) % q.size
+
+	return &headItem, nil
+}
+
+// Clear the queue data
+func (q *CircularQueue[T]) Clear() {
+	q.data = []T{}
+	q.front = 0
+	q.rear = 0
+	q.size = 0
+}
+
+// Contain checks if the value is in queue or not
+func (q *CircularQueue[T]) Contain(value T) bool {
+	for _, v := range q.data {
+		if reflect.DeepEqual(v, value) {
+			return true
+		}
+	}
+	return false
+}
+
+// Print queue data
+func (q *CircularQueue[T]) Print() {
+	fmt.Printf("%+v\n", q)
+}