Research on Go language data structure: application of queue and stack

In the Go language, the queue follows the first-in-first-out (FIFO) principle and is implemented using the list package in the standard library. It is often used in messaging systems; the stack follows the last-in-first-out (LIFO) principle and is often used for function call tracking and bracket matching. , which can be implemented using slices.

Go language data structure talk: application of queue and stack

Queue

Queue is a data structure that adheres to the first-in-first-out (FIFO) principle. This means that the earliest elements entered into the queue will be removed first. Queues are useful in the following scenarios:

• Message delivery systems, such as message queues
• Buffers, such as network request queues

Go Implementation of queues in the language

The most common way to implement queues in the Go language is to use container/liststandard library package:

import (
    "container/list"
)

// 定义队列类型
type Queue struct {
    items *list.List
}

// 创建队列
func NewQueue() *Queue {
    return &Queue{
        items: list.New(),
    }
}

// 进队
func (q *Queue) Enqueue(item interface{}) {
    q.items.PushBack(item)
}

// 出队
func (q *Queue) Dequeue() interface{} {
    if q.IsEmpty() {
        return nil
    }
    front := q.items.Front()
    q.items.Remove(front)
    return front.Value
}

// 判断队列是否为空
func (q *Queue) IsEmpty() bool {
    return q.items.Len() == 0
}

Practical combat Case: Message Queue

Message queue is a typical application scenario of queue. We can use the queue in the Go language to implement a message queue:

func main() {
    // 创建消息队列
    queue := NewQueue()

    // 向队列发送消息
    queue.Enqueue("消息 1")
    queue.Enqueue("消息 2")

    // 接收消息
    for {
        msg := queue.Dequeue()
        if msg == nil {
            break
        }
        fmt.Println(msg)
    }
}

Stack

The stack is a data structure that adheres to the last-in-first-out (LIFO) principle. This means that the last element added to the stack will be removed first. The stack is very useful in the following scenarios:

• Function call tracing
• Bracket matching

Implementation of stack in Go language

The simplest way to implement the stack in the Go language is to use slicing:

// 定义栈类型
type Stack []interface{}

// 进栈
func (s *Stack) Push(item interface{}) {
    *s = append(*s, item)
}

// 出栈
func (s *Stack) Pop() interface{} {
    if s.Empty() {
        return nil
    }
    top := (*s)[len(*s)-1]
    *s = (*s)[:len(*s)-1]
    return top
}

// 判断栈是否为空
func (s *Stack) Empty() bool {
    return len(*s) == 0
}

Practical case: bracket matching

The stack is a checker for bracket matching Good tool:

func isBalanced(expr string) bool {
    stack := Stack{}
    for _, char := range expr {
        if char == '(' || char == '[' || char == '{' {
            stack.Push(char)
        } else if char == ')' || char == ']' || char == '}' {
            if stack.Empty() {
                return false
            }
            top := stack.Pop()
            if (char == ')' && top != '(') || (char == ']' && top != '[') || (char == '}' && top != '{') {
                return false
            }
        }
    }
    return stack.Empty()
}

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