Question

我正在尝试快速排序但是我在VB.net中遇到堆栈溢出异常的问题。

当x = 3时，排序正常，当x = 5时，间歇性地排序;当x = 10时，排序有一半排序。

请告知，谢谢

    Dim x As Integer = 10
    Dim numArrray(x - 1) As Integer

    For i = 0 To x - 1
        Randomize()
        numArrray(i) = CInt(Rnd() * 9)
    Next

    Quicksort(numArrray, 0, numArrray.Length - 1)

    For i = 0 To x - 1
        Console.Write(numArrray(i))
    Next
    Console.ReadLine()
End Sub

Sub Quicksort(ByVal array() As Integer, ByVal min As Integer, ByVal max As Integer)
    Dim pivot As Integer

    If min < max Then
        pivot = partition(array, min, max)
        Quicksort(array, min, pivot - 1)
        Quicksort(array, pivot + 1, max)
    End If
End Sub

Function partition(ByVal array() As Integer, ByVal min As Integer, ByVal max As Integer) As Integer
    Dim pivot As Integer = array(max)
    Dim count As Integer = min - 1
    Dim placeholder As Integer

    For i = min To max - 1
        If array(i) < pivot Then
            count += 1
            placeholder = array(count)
            array(count) = array(i)
            array(i) = placeholder
        End If
    Next
    If array(max) < array(count + 1) Then
        placeholder = array(count + 1)
        array(count + 1) = array(max)
        array(max) = placeholder
    End If
    Return count

End Function

Answer 1

由于堆栈溢出，它将在Quicksort的嵌套调用中，查看分区我认为你有一个边界错误，根据这个算法版本en.wikipedia.org/wiki/Quicksort你应该返回count + 1来自分区，你当前的实现计数可以在min以下开始并保持这种无限回归的方式，因为你的嵌套调用将具有相同的输入（即如果你返回count = min - 1然后你做一个递归回调到Quicksort（array，pivot + 1，max）== Quicksort（array，min，max）

快速排序中的堆栈溢出异常

1 个答案: