将有序列表变成双向链表

2023-11-14 12:44:08

双向链表，也称为双链表，是一种特殊的链表，其中每个节点除了指向下一个节点的指针外，还指向之前一个节点的指针。这种数据结构在某些情况下比传统链表更有效，因为可以在两个方向上遍历它。

将有序列表转换为双向链表的过程涉及将每个节点连接到其前后一个节点。这可以通过遍历列表并将每个节点的指针指向其前后一个节点来实现。

以下是用 JavaScript 实现双向链表的示例：

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

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

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

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

  remove(value) {
    let current = this.head;

    while (current) {
      if (current.value === value) {
        if (current === this.head) {
          this.head = current.next;
        } else {
          current.prev.next = current.next;
        }

        if (current === this.tail) {
          this.tail = current.prev;
        } else {
          current.next.prev = current.prev;
        }

        return true;
      }

      current = current.next;
    }

    return false;
  }

  find(value) {
    let current = this.head;

    while (current) {
      if (current.value === value) {
        return current;
      }

      current = current.next;
    }

    return null;
  }

  print() {
    let current = this.head;

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