在C#中,PriorityQueue類沒有內置的方法來處理優先級反轉問題。但是,你可以通過維護一個最小堆(min-heap)來實現優先級隊列,并在插入和刪除元素時手動處理優先級反轉問題。
以下是一個簡單的示例,展示了如何在C#中實現一個支持優先級反轉處理的優先級隊列:
using System;
using System.Collections.Generic;
public class PriorityQueue<T> where T : IComparable<T>
{
private List<T> _elements = new List<T>();
public void Enqueue(T item, int priority)
{
var node = new Node<T>(item, priority);
int index = _elements.BinarySearch(node, Comparer<Node<T>>.Create((x, y) => x.Priority.CompareTo(y.Priority)));
if (index < 0)
{
index = ~index;
}
_elements.Insert(index, node);
// Rebalance the heap
while (index > 0 && _elements[(index - 1) / 2].Priority > node.Priority)
{
Swap(_elements, index, (index - 1) / 2);
index = (index - 1) / 2;
}
}
public T Dequeue()
{
if (_elements.Count == 0)
{
throw new InvalidOperationException("The priority queue is empty.");
}
var min = _elements[0];
_elements[0] = _elements[_elements.Count - 1];
_elements.RemoveAt(_elements.Count - 1);
// Rebalance the heap
int index = 0;
while (true)
{
int leftChildIndex = 2 * index + 1;
int rightChildIndex = 2 * index + 2;
int smallestChildIndex = -1;
if (leftChildIndex < _elements.Count && _elements[leftChildIndex].Priority < _elements[smallestChildIndex].Priority)
{
smallestChildIndex = leftChildIndex;
}
if (rightChildIndex < _elements.Count && _elements[rightChildIndex].Priority < _elements[smallestChildIndex].Priority)
{
smallestChildIndex = rightChildIndex;
}
if (smallestChildIndex == -1)
{
break;
}
Swap(_elements, index, smallestChildIndex);
index = smallestChildIndex;
}
return min;
}
private void Swap(List<T> list, int i, int j)
{
T temp = list[i];
list[i] = list[j];
list[j] = temp;
}
}
public class Node<T>
{
public T Item { get; }
public int Priority { get; }
public Node(T item, int priority)
{
Item = item;
Priority = priority;
}
}
在這個示例中,我們定義了一個泛型類PriorityQueue<T>
,它接受一個實現了IComparable<T>
接口的類型參數。我們使用一個List<T>
來存儲元素,并在插入和刪除元素時手動維護堆的平衡。這樣,我們可以確保優先級最高的元素始終位于堆的頂部。