双向(端)链表、栈、队列

 

双端链表

 

双端栈

 

双端队列

从实用角度,感受不出双端队列的好处,但其可以充当栈和队列的角色.

参考资料:http://baike.baidu.com/view/1627726.htm

Test

static void Main()
{var deque = new Deque<int>();Console.WriteLine("Stack:");//stackdeque.AddFirst(1);deque.AddFirst(2);deque.AddFirst(3);Console.WriteLine(deque.RemoveFirst());Console.WriteLine(deque.RemoveFirst());Console.WriteLine(deque.RemoveFirst());//queueConsole.WriteLine("Queue:");deque.AddFirst(1);deque.AddFirst(2);deque.AddFirst(3);Console.WriteLine(deque.RemoveLast());Console.WriteLine(deque.RemoveLast());Console.WriteLine(deque.RemoveLast());  }

当AddFirst和AddLast同时使用时则变成2个栈了

deque.AddFirst(1);
deque.AddFirst(2);
deque.AddFirst(3);
deque.AddLast(6);
deque.AddLast(7);
deque.AddLast(8);
Console.WriteLine(deque.RemoveLast());
Console.WriteLine(deque.RemoveLast());
Console.WriteLine(deque.RemoveLast());  
Console.WriteLine(deque.RemoveFirst());
Console.WriteLine(deque.RemoveFirst());
Console.WriteLine(deque.RemoveFirst());

简单实现

public interface IDeque<T>
{void AddFirst(T node);void AddLast(T node);T RemoveFirst();T RemoveLast();T PeekFirst();T PeekLast();
}public class Deque<T> : IDeque<T>
{private T[] _elements;private int head, end;public Deque(){_elements = new T[2];}//1,2,3,4public Deque(int capacity){_elements=new T[capacity];}public void AddFirst(T node){//loop indexif (--head < 0)head += _elements.Length;//val_elements[head] = node;//check capacityif (head == end)DoubleCapacity();}public void AddLast(T node){_elements[end] = node;if (++end < 0)end -= _elements.Length;if (head == end)DoubleCapacity();}private void DoubleCapacity(){int p = head;int n = _elements.Length;int r = n - p; int newCapacity = n << 1;T[] a = new T[newCapacity];Array.Copy(_elements, p, a, 0, r);Array.Copy(_elements, 0, a, r, p);_elements = (T[]) a;head = 0;end = n;}public T RemoveFirst(){T result = _elements[head]; _elements[head] = default(T);     if (++head >= _elements.Length)head -= _elements.Length;return result;}public T RemoveLast(){if (--end < 0)end += _elements.Length;T result = _elements[end];_elements[end] = default(T);return result;}public T PeekFirst(){return _elements[head];}public T PeekLast(){if (end == 0)return _elements[_elements.Length - 1];elsereturn _elements[end - 1];}public int GetLength(){return (end - head) & (_elements.Length - 1);}public bool IsEmpty(){return head == end;}public void Display(){foreach (var element in _elements){Console.Write(element+",");}Console.WriteLine();}
}

优先级队列PriorityQueue

两个主要的方法,我想的与源码不同,结果是相同的,没掌握一定技巧,以后回头再看吧

/// <summary>
/// 上滤，小为上，升序
/// </summary>
/// <param name="item">The item.</param>
private void PercolateUpAscending(T item)
{int i;for (i = Count - 1; i >= 0; i--){if (Compare(_heap[i], item) > 0){_heap[i + 1] = _heap[i];}elsebreak;}_heap[++i] = item;Count++;
}/// <summary>
/// 上滤，大为上，降序
/// </summary>
/// <param name="item">The item.</param>
private void PercolateUpDescending(T item)
{int i;for (i = Count - 1; i >= 0; i--){if (Compare(item, _heap[i]) > 0){_heap[i + 1] = _heap[i];}elsebreak;}_heap[++i] = item;Count++;
}