Implement fixed size Deque

Author: danielmbirochi

deque/fixed_size_deque.go

@@ -0,0 +1,58 @@
+package deque
+
+type FixedSizeDeque struct {
+	items [5]int
+	front int
+	back  int
+}
+
+func (d *FixedSizeDeque) EnqueueFront(item int) bool {
+	if d.IsFull() {
+		return false
+	}
+	d.front = (d.front - 1 + len(d.items)) % len(d.items)
+	d.items[d.front] = item
+	return true
+}
+
+func (d *FixedSizeDeque) EnqueueBack(item int) bool {
+	if d.IsFull() {
+		return false
+	}
+	d.items[d.back] = item
+	d.back = (d.back + 1) % len(d.items)
+	return true
+}
+
+func (d *FixedSizeDeque) DequeueFront() (int, bool) {
+	if d.IsEmpty() {
+		return 0, false
+	}
+	front := d.items[d.front]
+	d.front = (d.front + 1) % len(d.items)
+	return front, true
+}
+
+func (d *FixedSizeDeque) DequeueBack() (int, bool) {
+	if d.IsEmpty() {
+		return 0, false
+	}
+	d.back = (d.back - 1 + len(d.items)) % len(d.items)
+	rear := d.items[d.back]
+	return rear, true
+}
+
+func (d *FixedSizeDeque) IsEmpty() bool {
+	return d.front == d.back
+}
+
+func (d *FixedSizeDeque) IsFull() bool {
+	return (d.back+1)%len(d.items) == d.front
+}
+
+func (d *FixedSizeDeque) Size() int {
+	if d.IsEmpty() {
+		return 0
+	}
+	return (d.back - d.front + len(d.items)) % len(d.items)
+}