Deque<T> is a .NET implementation of double-ended queue.

using Unageek.Collections;

var queue = new Deque<string>();
queue.AddLast("one");
queue.AddLast("two");
queue.AddLast("three");

var stack = new Deque<string>();
stack.AddFirst("three");
stack.AddFirst("two");
stack.AddFirst("one");

Console.WriteLine(queue.SequenceEqual(stack)); // True

• Drop-in replacement for List<T>

  Deque<T> implements the same interfaces, methods, and properties as List<T>, including random access, bulk insertion/removal, and binary search.

• Performance

  Random insertion and removal are expected to be twice as fast as List<T>.

• Additional methods

  Deque<T> also provides the following methods:

  • void AddFirst(T item)
  • void AddLast(T item) (equivalent to Add)
  • void RemoveFirst()
  • void RemoveLast()
  • T PeekFirst()
  • T PeekLast()
  • T PopFirst()
  • T PopLast()
  • bool TryPeekFirst(out T item)
  • bool TryPeekLast(out T item)
  • bool TryPopFirst(out T item)
  • bool TryPopLast(out T item)

• The maximum number of elements a Deque<T> can hold is 2³⁰ = 1,073,741,824. If you try to add more items, an OutOfMemoryException is thrown.

• The capacity of a Deque<T> can only be zero or a power of two (up to 2³⁰).

• Serialization is not supported.

.NET 6+ is supported.