> For the complete documentation index, see [llms.txt](https://mm.ricky.moe/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mm.ricky.moe/algorithm/algorithm-and-data-structure/shu-ju-jie-gou/dui-lie.md).

# 队列

队列数据结构是遵循先进先出的有序集合，例如 js 的任务队列

## 实现

```javascript
let Queue = (function() {
  let items = new WeakMap()
  class Queue {
    constructor () {
      items.set(this, [])
    }
    enqueue (v) { // 入列
      items.get(this).push(v)
    }
    dequeue () { // 出列
      return items.get(this).shift()
    }
    front () { // 获取当前队列首位
      return items.get(this)[0]
    }
    size () { // 栈长度
      return items.get(this).length
    }
    isEmpty () { // 栈是否为空
      return items.get(this).length === 0
    }
    clear () { // 清空栈
      items.get(this).length = 0
    }
  }
  return Queue
})()
```

实现方式跟栈数据结构一样，只是实现的具体的方法不同。出栈实现的是数组的`pop`，出列实现的是数组的`shift`。


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://mm.ricky.moe/algorithm/algorithm-and-data-structure/shu-ju-jie-gou/dui-lie.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.