作为一项学校作业,我应该使用至少 2 个线程来执行多线程快速排序算法,但我的代码存在一些我似乎无法修复的问题。
编辑:这就是它不是多线程时的样子。我已经确认这有效。
public class Sorter
{
private int[] mInts;
public void QuickSort()
{
QuickSort(mInts, 0, mInts.Length - 1);
}
public Sorter(int[] ints)
{
mInts = ints;
}
private int Partition(int[] ints, int left, int right)
{
int pivotIndex = (right + left) / 2;
int pivotValue = ints[pivotIndex];
Swap(ints, right, pivotIndex);
int storeIndex = left;
for (int i = left; i <= right - 1; i++)
{
if (ints[i] < pivotValue)
{
Swap(ints, storeIndex, i);
storeIndex++;
}
}
Swap(ints, storeIndex, right);
return storeIndex;
}
private void Swap(int[] ints, int x, int y)
{
int temp = ints[x];
ints[x] = ints[y];
ints[y] = temp;
}
private void QuickSort(int[] ints, int left, int right)
{
if (left < right)
{
int newIndex = Partition(ints, left, right);
QuickSort(ints, left, newIndex - 1);
QuickSort(ints, newIndex + 1, right);
}
}
上面的工作正常,下面的代码没有。现在它没有正确排序,在我看来,加粗的代码段必须位于其他地方......还是什么?我很难理解线程编程,所以我希望有人能给我一些关于如何解决这个问题的指导,如果可能的话,不必重组我的整个程序。以下是我在线程版本方面取得的进展。
public class Sorter
{
private int[] mInts;
Thread myThread = null;
int numThreads = 0;
int maxThreads = 10;
public void QuickSort()
{
QuickSort(mInts, 0, mInts.Length - 1);
}
public Sorter(int[] ints)
{
mInts = ints;
}
private int Partition(int[] ints, int left, int right)
{
int pivotIndex = (right + left) / 2;
int pivotValue = ints[pivotIndex];
Swap(ints, right, pivotIndex);
int storeIndex = left;
for (int i = left; i <= right - 1; i++)
{
if (ints[i] < pivotValue)
{
Swap(ints, storeIndex, i);
storeIndex++;
}
}
Swap(ints, storeIndex, right);
return storeIndex;
}
private void Swap(int[] ints, int x, int y)
{
int temp = ints[x];
ints[x] = ints[y];
ints[y] = temp;
}
private void QuickSort(int[] ints, int left, int right)
{
if (left < right)
{
int newIndex = Partition(ints, left, right);
if (numThreads < maxThreads)
{
numThreads++;
myThread = new Thread(new ParameterizedThreadStart(startSort));
myThread.Start(new SortParameters(this, ints, left, newIndex - 1));
**QuickSort(ints, newIndex + 1, right);**
}
}
}
static void startSort(Object obj)
{
SortParameters sortParams = (SortParameters)obj;
sortParams.instance.QuickSort(sortParams.ints, sortParams.left, sortParams.right);
}
public class SortParameters
{
public Sorter instance;
public int[] ints;
public int left;
public int right;
public SortParameters(Sorter instance, int[] ints, int left, int right)
{
this.instance = instance;
this.ints = ints;
this.left = left;
this.right = right;
}
}
}
谢谢你的帮助!