using System;

public class Program

{

    private static void Quick_Sort(int[] arr, int left, int right) 

        {

            if (left < right)

            {

                int pivot = Partition(arr, left, right);

​

                if (pivot > 1) {

                    Quick_Sort(arr, left, pivot - 1);

                }

                if (pivot + 1 < right) {

                    Quick_Sort(arr, pivot + 1, right);

                }

            }

        }

​

        private static int Partition(int[] arr, int left, int right)

        {

            int pivot = arr[left];

            while (true) 

            {

​

                while (arr[left] < pivot) 

                {

                    left++;

                }

​

                while (arr[right] > pivot)

                {

                    right--;

                }

​

                if (left < right)

                {

                    if (arr[left] == arr[right]) return right;

​

                    int temp = arr[left];

                    arr[left] = arr[right];

                    arr[right] = temp;

​

​

                }

                else 

                {

                    return right;

                }

            }

        }

    public static void Main()

    {

        int[] arr = new int[] { 2, 5, -4, 11, 0, 18, 22, 67, 51, 6 };

​

            Console.WriteLine("Original array : ");

            foreach (var item in arr)

            {

                Console.Write(" " + item);    

            }

            Console.WriteLine();

​

            Quick_Sort(arr, 0, arr.Length-1);

            Console.WriteLine();

            Console.WriteLine("Sorted array : ");

           foreach (var item in arr)

            {

                Console.Write(" " + item);

            }

            Console.WriteLine();

    }

}