JS实现的链表：一行代码搞定，再也不用因没有链表而苦恼！

2023-12-05 22:51:03

一、链表简介

链表是一种线性的数据结构，由一系列被称为“节点”的元素组成。每个节点包含一个值和指向下一个节点的指针。链表的主要优点是易于插入和删除节点，而无需移动其他节点。

二、在 JavaScript 中实现链表

令人惊讶的是，JavaScript 并没有内置的链表数据结构。但是，我们可以使用一行代码轻松实现一个链表。

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

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

  append(value) {
    const newNode = new Node(value);

    if (this.head === null) {
      this.head = newNode;
      this.tail = newNode;
    } else {
      this.tail.next = newNode;
      this.tail = newNode;
    }
  }

  prepend(value) {
    const newNode = new Node(value);

    if (this.head === null) {
      this.head = newNode;
      this.tail = newNode;
    } else {
      newNode.next = this.head;
      this.head = newNode;
    }
  }

  insertAfter(value, afterValue) {
    const newNode = new Node(value);

    let currentNode = this.head;

    while (currentNode) {
      if (currentNode.value === afterValue) {
        newNode.next = currentNode.next;
        currentNode.next = newNode;

        if (currentNode === this.tail) {
          this.tail = newNode;
        }

        return;
      }

      currentNode = currentNode.next;
    }

    throw new Error("Value not found in the list.");
  }

  delete(value) {
    if (this.head === null) {
      return;
    }

    if (this.head.value === value) {
      this.head = this.head.next;

      if (this.head === null) {
        this.tail = null;
      }

      return;
    }

    let currentNode = this.head;
    let previousNode = null;

    while (currentNode) {
      if (currentNode.value === value) {
        previousNode.next = currentNode.next;

        if (currentNode === this.tail) {
          this.tail = previousNode;
        }

        return;
      }

      previousNode = currentNode;
      currentNode = currentNode.next;
    }

    throw new Error("Value not found in the list.");
  }

  print() {
    let currentNode = this.head;

    while (currentNode) {
      console.log(currentNode.value);
      currentNode = currentNode.next;
    }
  }
}