unsafe
{
    const int ArraySize = 10;

    // Allocate memory on the stack using stackalloc
    int* arr = stackalloc int[ArraySize];

    // Initialize array with random values
    Random rand = new(42);
    Console.WriteLine("Before sorting:");
    for (int i = 0; i < ArraySize; i++)
    {
        arr[i] = rand.Next(1, 100);
        Console.Write($"{arr[i]} ");
    }
    Console.WriteLine();

    // Execute QuickSort
    QuickSort(arr, 0, ArraySize - 1);

    // Print sorted result
    Console.WriteLine("\nAfter sorting:");
    for (int i = 0; i < ArraySize; i++)
    {
        Console.Write($"{arr[i]} ");
    }
    Console.WriteLine();

    static void QuickSort(int* arr, int left, int right)
    {
        if (left >= right) return;

        int pivotIndex = Partition(arr, left, right);
        QuickSort(arr, left, pivotIndex - 1);
        QuickSort(arr, pivotIndex + 1, right);
    }

    static int Partition(int* arr, int left, int right)
    {
        int pivot = arr[right];
        int i = left - 1;

        for (int j = left; j < right; j++)
        {
            if (arr[j] <= pivot)
            {
                i++;
                (arr[i], arr[j]) = (arr[j], arr[i]);  // Tuple swap
            }
        }

        (arr[i + 1], arr[right]) = (arr[right], arr[i + 1]);
        return i + 1;
    }
}

public static class NativeExports
{
    [UnmanagedCallersOnly(EntryPoint = "add")]
    public static int Add(int a, int b) => a + b;
}