circular_queue.go

package main

type CircularQueue struct {
	items []interface{}
	head  int
	tail  int
	size  int
}

func NewCircularQueue(k int) *CircularQueue {
	return &CircularQueue{
		items: make([]interface{}, k),
		head:  -1,
		tail:  -1,
		size:  0,
	}
}

func (cq *CircularQueue) Enqueue(item interface{}) bool {
	if cq.IsFull() {
		return false
	}
	if cq.IsEmpty() {
		cq.head = 0
	}
	cq.tail = (cq.tail + 1) % len(cq.items)
	cq.items[cq.tail] = item
	cq.size++
	return true
}

func (cq *CircularQueue) Dequeue() interface{} {
	if cq.IsEmpty() {
		return nil
	}
	item := cq.items[cq.head]
	if cq.head == cq.tail {
		cq.head = -1
		cq.tail = -1
	} else {
		cq.head = (cq.head + 1) % len(cq.items)
	}
	cq.size--
	return item
}

func (cq *CircularQueue) IsEmpty() bool {
	return cq.size == 0
}

func (cq *CircularQueue) IsFull() bool {
	return cq.size == len(cq.items)
}

func (cq *CircularQueue) GetSize() int {
	return cq.size
}