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链表实现js

2026-01-14 14:50:18JavaScript

链表的基本概念

链表是一种线性数据结构，由一系列节点组成，每个节点包含数据和一个指向下一个节点的指针（单向链表）或两个指针（双向链表）。与数组不同，链表在内存中非连续存储，插入和删除操作更高效，但随机访问效率较低。

单向链表的实现

以下是用JavaScript实现单向链表的核心代码：

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

class LinkedList {
  constructor() {
    this.head = null;
    this.size = 0;
  }

  // 在链表尾部添加节点
  add(data) {
    const node = new Node(data);
    if (!this.head) {
      this.head = node;
    } else {
      let current = this.head;
      while (current.next) {
        current = current.next;
      }
      current.next = node;
    }
    this.size++;
  }

  // 在指定位置插入节点
  insertAt(data, index) {
    if (index < 0 || index > this.size) return false;
    const node = new Node(data);
    if (index === 0) {
      node.next = this.head;
      this.head = node;
    } else {
      let current = this.head;
      let prev;
      for (let i = 0; i < index; i++) {
        prev = current;
        current = current.next;
      }
      node.next = current;
      prev.next = node;
    }
    this.size++;
    return true;
  }

  // 删除指定位置的节点
  removeFrom(index) {
    if (index < 0 || index >= this.size) return null;
    let removedNode;
    if (index === 0) {
      removedNode = this.head;
      this.head = this.head.next;
    } else {
      let current = this.head;
      let prev;
      for (let i = 0; i < index; i++) {
        prev = current;
        current = current.next;
      }
      removedNode = current;
      prev.next = current.next;
    }
    this.size--;
    return removedNode.data;
  }

  // 打印链表数据
  print() {
    let current = this.head;
    let result = '';
    while (current) {
      result += `${current.data} -> `;
      current = current.next;
    }
    console.log(result + 'null');
  }
}

双向链表的实现

双向链表的节点包含前后两个指针，实现代码如下：

class DoublyNode {
  constructor(data) {
    this.data = data;
    this.prev = null;
    this.next = null;
  }
}

class DoublyLinkedList {
  constructor() {
    this.head = null;
    this.tail = null;
    this.size = 0;
  }

  // 尾部添加节点
  add(data) {
    const node = new DoublyNode(data);
    if (!this.head) {
      this.head = node;
      this.tail = node;
    } else {
      node.prev = this.tail;
      this.tail.next = node;
      this.tail = node;
    }
    this.size++;
  }

  // 删除指定位置节点
  removeAt(index) {
    if (index < 0 || index >= this.size) return null;
    let current = this.head;
    if (index === 0) {
      this.head = current.next;
      if (this.head) this.head.prev = null;
      else this.tail = null;
    } else if (index === this.size - 1) {
      current = this.tail;
      this.tail = current.prev;
      this.tail.next = null;
    } else {
      for (let i = 0; i < index; i++) {
        current = current.next;
      }
      current.prev.next = current.next;
      current.next.prev = current.prev;
    }
    this.size--;
    return current.data;
  }
}