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js实现队列

2026-04-06 23:04:08JavaScript

队列的基本概念

队列是一种遵循先进先出（FIFO）原则的数据结构。元素从队尾入队，从队头出队。JavaScript中可通过数组或链表实现队列。

js实现队列

基于数组的实现

利用数组的push和shift方法模拟队列操作，但shift操作的时间复杂度为O(n)，可能影响性能。

js实现队列

class ArrayQueue {
  constructor() {
    this.items = [];
  }

  enqueue(element) {
    this.items.push(element);
  }

  dequeue() {
    return this.items.shift();
  }

  peek() {
    return this.items[0];
  }

  isEmpty() {
    return this.items.length === 0;
  }

  size() {
    return this.items.length;
  }

  clear() {
    this.items = [];
  }
}

基于链表的实现

链表实现可避免数组shift的性能问题，每个节点存储值和指向下一个节点的引用。

class Node {
  constructor(value) {
    this.value = value;
    this.next = null;
  }
}

class LinkedListQueue {
  constructor() {
    this.head = null;
    this.tail = null;
    this.length = 0;
  }

  enqueue(value) {
    const newNode = new Node(value);
    if (!this.head) {
      this.head = newNode;
      this.tail = newNode;
    } else {
      this.tail.next = newNode;
      this.tail = newNode;
    }
    this.length++;
  }

  dequeue() {
    if (!this.head) return null;
    const removedNode = this.head;
    this.head = this.head.next;
    if (!this.head) this.tail = null;
    this.length--;
    return removedNode.value;
  }

  peek() {
    return this.head?.value;
  }

  isEmpty() {
    return this.length === 0;
  }

  size() {
    return this.length;
  }

  clear() {
    this.head = null;
    this.tail = null;
    this.length = 0;
  }
}

循环队列的实现

循环队列通过固定大小的数组和指针优化空间利用率，避免数据搬移。

class CircularQueue {
  constructor(k) {
    this.size = k;
    this.queue = new Array(k);
    this.head = -1;
    this.tail = -1;
  }

  enqueue(value) {
    if (this.isFull()) return false;
    if (this.isEmpty()) this.head = 0;
    this.tail = (this.tail + 1) % this.size;
    this.queue[this.tail] = value;
    return true;
  }

  dequeue() {
    if (this.isEmpty()) return false;
    if (this.head === this.tail) {
      this.head = -1;
      this.tail = -1;
    } else {
      this.head = (this.head + 1) % this.size;
    }
    return true;
  }

  Front() {
    return this.isEmpty() ? -1 : this.queue[this.head];
  }

  Rear() {
    return this.isEmpty() ? -1 : this.queue[this.tail];
  }

  isEmpty() {
    return this.head === -1;
  }

  isFull() {
    return (this.tail + 1) % this.size === this.head;
  }
}