lancet/docs/datastructure/queue.md

Queue

A queue is a kind of linear table. It only allows delete operations at the front of the table and insert operations at the rear of the table. This package includes ArrayQueue, LinkedQueue, CircularQueue, and PriorityQueue.

Source

• https://github.com/duke-git/lancet/blob/main/datastructure/queue/arrayqueue.go
• https://github.com/duke-git/lancet/blob/main/datastructure/queue/linkedqueue.go
• https://github.com/duke-git/lancet/blob/main/datastructure/queue/circularqueue.go
• https://github.com/duke-git/lancet/blob/main/datastructure/queue/priorityqueue.go

Usage

import (
    stack "github.com/duke-git/lancet/v2/datastructure/stack"
)

Index

1. ArrayQueue

• NewArrayQueue
• Enqueue
• Dequeue
• Front
• Back
• Front
• IsEmpty
• Clear
• Contain

2. LinkedStack

Documentation

1. ArrayQueue

Common queue implemented by slice.

NewArrayQueue

Return a ArrayQueue pointer with specific capacity

Signature:

func NewArrayQueue[T any](capacity int) *ArrayQueue[T]

type ArrayQueue[T any] struct {
	items    []T
	head     int
	tail     int
	capacity int
	size     int
}

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    fmt.Println(q.Data()) // []
}

Data

Get all queue data

Signature:

func (q *ArrayQueue[T]) Data() []T

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    fmt.Println(q.Data()) // []
}

Enqueue

Put element into queue, if queue is full, return false

Signature:

func (q *ArrayQueue[T]) Enqueue(item T) bool

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Data()) // 1,2,3
}

Dequeue

Remove head element of queue and return it

Signature:

func (q *ArrayQueue[T]) Dequeue() (T, bool)

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Dequeue()) // 1
    fmt.Println(q.Data()) // 2,3
}

Front

Just get head element of queue

Signature:

func (q *ArrayQueue[T]) Front() T

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Front()) // 1
    fmt.Println(q.Data()) // 1,2,3
}

Back

Just get tail element of queue

Signature:

func (q *ArrayQueue[T]) Back() T

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Back()) // 3
    fmt.Println(q.Data()) // 1,2,3
}

Size

Get the number of elements in queue

Signature:

func (q *ArrayQueue[T]) Size() int

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Size()) // 3
}

IsEmpty

Check if queue is empty or not

Signature:

func (q *ArrayQueue[T]) IsEmpty() bool

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    fmt.Println(q.IsEmpty()) // true

    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.IsEmpty()) // false
}

Clear

Clean all data in queue

Signature:

func (q *ArrayQueue[T]) Clear()

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)
    q.Clear()

    fmt.Println(q.IsEmpty()) // true
}

Contain

checks if the value is in queue or not

Signature:

func (q *ArrayQueue[T]) Contain(value T) bool

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewArrayQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Contain(1)) // true
    fmt.Println(q.Contain(4)) // false
}

2. LinkedQueue

Common queue implemented by link.

NewLinkedQueue

Return a LinkedQueue pointer with

Signature:

func NewLinkedQueue[T any]() *LinkedQueue[T]

type LinkedQueue[T any] struct {
	head   *datastructure.QueueNode[T]
	tail   *datastructure.QueueNode[T]
	length int
}
type QueueNode[T any] struct {
	Value T
	Next  *QueueNode[T]
}

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int]()
    fmt.Println(q.Data()) // []
}

Data

Get all queue data

Signature:

func (q *LinkedQueue[T]) Data() []T

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int]()
    fmt.Println(q.Data()) // []
}

Enqueue

Put element into queue

Signature:

func (q *LinkedQueue[T]) Enqueue(value T)

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Data()) // 1,2,3
}

Dequeue

Remove head element of queue and return it

Signature:

func (q *LinkedQueue[T]) Dequeue() (T, error)

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Dequeue()) // 1
    fmt.Println(q.Data()) // 2,3
}

Front

Just get head element of queue

Signature:

func (q *LinkedQueue[T]) Front() (*T, error)

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Front()) // 1
    fmt.Println(q.Data()) // 1,2,3
}

Back

Just get tail element of queue

Signature:

func (q *LinkedQueue[T]) Back() (*T, error) 

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Back()) // 3
    fmt.Println(q.Data()) // 1,2,3
}

Size

Get the number of elements in queue

Signature:

func (q *LinkedQueue[T]) Size() int

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Size()) // 3
}

IsEmpty

Check if queue is empty or not

Signature:

func (q *LinkedQueue[T]) IsEmpty() bool

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int](5)
    fmt.Println(q.IsEmpty()) // true

    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.IsEmpty()) // false
}

Clear

Clean all data in queue

Signature:

func (q *LinkedQueue[T]) Clear()

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)
    q.Clear()

    fmt.Println(q.IsEmpty()) // true
}

Contain

checks if the value is in queue or not

Signature:

func (q *LinkedQueue[T]) Contain(value T) bool

Example:

package main

import (
    "fmt"
    queue "github.com/duke-git/lancet/v2/datastructure/queue"
)

func main() {
    q := queue.NewLinkedQueue[int](5)
    q.Enqueue(1)
    q.Enqueue(2)
    q.Enqueue(3)

    fmt.Println(q.Contain(1)) // true
    fmt.Println(q.Contain(4)) // false
}