using System.Collections.Generic;

namespace GFGGame
{
    /// <summary>
    /// 唯一队列
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class UniqueQueue<T>
    {
        private Queue<T> queue = new Queue<T>();
        private HashSet<T> set = new HashSet<T>();

        public bool Contains(T item)
        {
            return set.Contains(item);
        }
        
        public void Enqueue(T item)
        {
            if (!set.Contains(item))
            {
                queue.Enqueue(item);
                set.Add(item);
            }
        }

        public T Dequeue()
        {
            T item = queue.Dequeue();
            set.Remove(item);
            return item;
        }

        public int Count => queue.Count;
    }
}