public static class Quicksort
    {
        public static void SortInline(int[] arr)
        {
            Inline(arr, 0, arr.Length - 1);
        }

        private static void Inline(int[] arr, int left, int right)
        {
            if (left >= right) return;

            int pivot = arr[left];
            int leftPoint = left - 1;
            int pIndex = right + 1;
            int temp;

            while (true)
            {
                do { pIndex--; } while (arr[pIndex] > pivot);
                do { leftPoint++; } while (arr[leftPoint] < pivot);

                if (leftPoint < pIndex)
                {
                    temp = arr[leftPoint];
                    arr[leftPoint] = arr[pIndex];
                    arr[pIndex] = temp;
                }
                else { break; }
            }

            Inline( arr, left, pIndex);
            Inline( arr, pIndex + 1, right);
        }

        public static void SortNonInline(int[] arr)
        {
            NonInline(arr, 0, arr.Length - 1);
        }

        private static void NonInline(int[] arr, int left, int right)
        {
            if (left >= right) return;

            var pIndex = Partition(arr, left, right);
            NonInline(arr, left, pIndex);
            NonInline(arr, pIndex + 1, right);
        }

        private static int Partition(int[] arr, int left, int right)
        {
            int pivot = arr[left];
            int leftPoint = left - 1;
            int pIndex = right + 1;
            int temp;

            while (true)
            {
                do { pIndex--; } while (arr[pIndex] > pivot);
                do { leftPoint++; } while (arr[leftPoint] < pivot);

                if (leftPoint < pIndex)
                {
                    temp = arr[leftPoint];
                    arr[leftPoint] = arr[pIndex];
                    arr[pIndex] = temp;
                }
                else { break; }
            }
            return pIndex;
        }
    }