链表

每个节点由数据和到序列中下一个节点的引用组成。这种结构允许在迭代期间有效地从序列中的任何位置插入或删除元素。链表的一个缺点是访问时间是线性的(而且难以管道化)。更快的访问，如随机访问，是不可行的。

复杂度

时间复杂度

Access	Search	Insertion	Deletion
O(n)	O(n)	O(1)	O(1)

空间复杂度

O(n)

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

  toString(callback) {
    return callback ? callback(this.value) : `${this.value}`;
  }
}

class LinkedList {
  /**
   * @param {Function} [comparatorFunction]
   */
  constructor(comparatorFunction) {
    /** @var LinkedListNode */
    this.head = null;

    /** @var LinkedListNode */
    this.tail = null;

    this.compare = new Comparator(comparatorFunction);
  }

  /**
   * @param {*} value
   * @return {LinkedList}
   */
  prepend(value) {
    // Make new node to be a head.
    const newNode = new LinkedListNode(value, this.head);
    this.head = newNode;

    // If there is no tail yet let's make new node a tail.
    if (!this.tail) {
      this.tail = newNode;
    }

    return this;
  }

  /**
   * @param {*} value
   * @return {LinkedList}
   */
  append(value) {
    const newNode = new LinkedListNode(value);

    // If there is no head yet let's make new node a head.
    if (!this.head) {
      this.head = newNode;
      this.tail = newNode;

      return this;
    }

    // Attach new node to the end of linked list.
    this.tail.next = newNode;
    this.tail = newNode;

    return this;
  }

  /**
   * @param {*} value
   * @return {LinkedListNode}
   */
  delete(value) {
    if (!this.head) {
      return null;
    }

    let deletedNode = null;

    // If the head must be deleted then make next node that is differ
    // from the head to be a new head.
    while (this.head && this.compare.equal(this.head.value, value)) {
      deletedNode = this.head;
      this.head = this.head.next;
    }

    let currentNode = this.head;

    if (currentNode !== null) {
      // If next node must be deleted then make next node to be a next next one.
      while (currentNode.next) {
        if (this.compare.equal(currentNode.next.value, value)) {
          deletedNode = currentNode.next;
          currentNode.next = currentNode.next.next;
        } else {
          currentNode = currentNode.next;
        }
      }
    }

    // Check if tail must be deleted.
    if (this.compare.equal(this.tail.value, value)) {
      this.tail = currentNode;
    }

    return deletedNode;
  }

  /**
   * @param {Object} findParams
   * @param {*} findParams.value
   * @param {function} [findParams.callback]
   * @return {LinkedListNode}
   */
  find({ value = undefined, callback = undefined }) {
    if (!this.head) {
      return null;
    }

    let currentNode = this.head;

    while (currentNode) {
      // If callback is specified then try to find node by callback.
      if (callback && callback(currentNode.value)) {
        return currentNode;
      }

      // If value is specified then try to compare by value..
      if (value !== undefined && this.compare.equal(currentNode.value, value)) {
        return currentNode;
      }

      currentNode = currentNode.next;
    }

    return null;
  }

  /**
   * @return {LinkedListNode}
   */
  deleteTail() {
    const deletedTail = this.tail;

    if (this.head === this.tail) {
      // There is only one node in linked list.
      this.head = null;
      this.tail = null;

      return deletedTail;
    }

    // If there are many nodes in linked list...

    // Rewind to the last node and delete "next" link for the node before the last one.
    let currentNode = this.head;
    while (currentNode.next) {
      if (!currentNode.next.next) {
        currentNode.next = null;
      } else {
        currentNode = currentNode.next;
      }
    }

    this.tail = currentNode;

    return deletedTail;
  }

  /**
   * @return {LinkedListNode}
   */
  deleteHead() {
    if (!this.head) {
      return null;
    }

    const deletedHead = this.head;

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

    return deletedHead;
  }

  /**
   * @param {*[]} values - Array of values that need to be converted to linked list.
   * @return {LinkedList}
   */
  fromArray(values) {
    values.forEach(value => this.append(value));

    return this;
  }

  /**
   * @return {LinkedListNode[]}
   */
  toArray() {
    const nodes = [];

    let currentNode = this.head;
    while (currentNode) {
      nodes.push(currentNode);
      currentNode = currentNode.next;
    }

    return nodes;
  }

  /**
   * @param {function} [callback]
   * @return {string}
   */
  toString(callback) {
    return this.toArray().map(node => node.toString(callback)).toString();
  }

  /**
   * Reverse a linked list.
   * @returns {LinkedList}
   */
  reverse() {
    let currNode = this.head;
    let prevNode = null;
    let nextNode = null;

    while (currNode) {
      // Store next node.
      nextNode = currNode.next;

      // Change next node of the current node so it would link to previous node.
      currNode.next = prevNode;

      // Move prevNode and currNode nodes one step forward.
      prevNode = currNode;
      currNode = nextNode;
    }

    // Reset head and tail.
    this.tail = this.head;
    this.head = prevNode;

    return this;
  }
}

class Comparator {

  constructor(compareFunction) {
    this.compare = compareFunction || Comparator.defaultCompareFunction;
  }

  static defaultCompareFunction(a, b) {
    if (a === b) {
      return 0;
    }

    return a < b ? -1 : 1;
  }

  equal(a, b) {
    return this.compare(a, b) === 0;
  }

  lessThan(a, b) {
    return this.compare(a, b) < 0;
  }

  greaterThan(a, b) {
    return this.compare(a, b) > 0;
  }

  lessThanOrEqual(a, b) {
    return this.lessThan(a, b) || this.equal(a, b);
  }

  greaterThanOrEqual(a, b) {
    return this.greaterThan(a, b) || this.equal(a, b);
  }

  reverse() {
    const compareOriginal = this.compare;
    this.compare = (a, b) => compareOriginal(b, a);
  }
}