using System;

public class Program

{

    public static void Main()

    {

        var input = new int[]{ 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 

                1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0 };

        BinarySort(input);

        foreach(var i in input)

        {

            Console.WriteLine(i);

        }

        Console.WriteLine();

        var input2 = new int[]{ 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 

                1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0 };

        BinarySort2(input2);

        foreach(var i in input2)

        {

            Console.WriteLine(i);

        }

    }

    public static void BinarySort(int[] array)

    {

        int count = 0;

        int j = -1;

        for (int i = 0; i < array.Length; i++)

        {

            if (array[i] == 0)

            {

                j++;

                var temp = array[j];

                array[j] = array[i];

                array[i] = temp;

                count++;

            }

        }

        Console.WriteLine("Number of swaps = {0}", count);

    }

    public static void BinarySort2(int[] array)

    {

        int count = 0;

        int left = 0;

        int right = array.Length - 1;

        while(left < right)

        {

            if (array[left] == 1)

            {

                while(array[right] != 0 && right > left)

                {

                    right--;

                }

                var temp = array[left];

                array[left] = array[right];

                array[right] = temp;

                count++;

                right--;

            }

            left++;

        }

        Console.WriteLine("Number of swaps = {0}", count);

    }

}