type List interface {
	Add(value interface{})
	Clear()
	Get(index int) (interface{}, error)
	IndexOf(value interface{}) int
	Insert(index int, value interface{}) error
	IsEmpty() bool
	Remove(index int) (interface{}, error)
	Size() int
}

type Stack interface {
	Clear()
	IsEmpty() bool
	Peek() (interface{}, error)
	Pop() (interface{}, error)
	Push(value interface{})
	Size() int
}

type Queue interface {
	Clear()
	IsEmpty() bool
	Offer(value interface{})
	Peek() (interface{}, error)
	Poll() (interface{}, error)
	Size() int
}

type Dequeue interface {
	Clear()
	IsEmpty() bool
	OfferFirst(value interface{})
	OfferLast(value interface{})
	PeekFirst() (interface{}, error)
	PeekLast() (interface{}, error)
	PollFirst() (interface{}, error)
	PollLast() (interface{}, error)
	Size() int
}

type PriorityQueue interface {
	Clear()
	IsEmpty() bool
	Offer(value interface{}, priority int)
	Peek() (interface{}, error)
	Poll() (interface{}, error)
	Size() int
}