import { LinkedList } from './LinkedList';

/**
 * FIFO queue implemented with O(1) enqueue and dequeue operations
 */
export class Queue<T> {
  private _list: LinkedList<T> = new LinkedList<T>();

  /**
   * Peak the tip value
   */
  public peak(): T {
    return this._list.head && this._list.head.value;
  }

  /**
   * Returns the length of the queue
   */
  get length(): number {
    return this._list.length;
  }

  /**
   * Enqueue a value
   */
  public enqueue(value: T): void {
    this._list.add(value);
  }

  /**
   * Dequeue top most value
   */
  public dequeue(): T {
    return this._list.remove(0);
  }
}