using System;

using System.Collections.Generic;

using NUnit.Framework;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}

​

public class Node : IEquatable<Node>

{

    public int row

    {

        get;

        set;

    }

​

    public int column

    {

        get;

        set;

    }

​

    public override int GetHashCode()

    {

        return column.GetHashCode() + row.GetHashCode();

    }

​

    public override bool Equals(object obj)

    {

        return Equals(obj as Node);

    }

​

    public bool Equals(Node obj)

    {

        if (obj == null)

        {

            return false;

        }

        else

        {

            return obj.column == column && obj.row == row;

        }

    }

​

    public void AddNeighbors(IList<Node> island, bool[, ] arr)

    {

        if (island == null)

        {

            throw new ArgumentNullException(nameof(arr));

        }

​

        if (arr == null)

        {

            throw new ArgumentNullException(nameof(arr));

        }

​

        var r = row == 0 ? 0 : row - 1;

        var c = column == 0 ? 0 : column - 1;

        var rows = arr.GetLength(0);

        var columns = arr.GetLength(1);

        while (r < row + 2)

        {

            while (c < column + 2)

            {

                //if arr[r,c] != this and r and c are within bounds of array

                if (r < rows && c < columns && (r != row || c != column))

                {

                    if (arr[r, c])

                    {

                        var neighbor = new Node()

                        {row = r, column = c};

                        if (!island.Contains(neighbor))

                        {

                            island.Add(neighbor);

                            neighbor.AddNeighbors(island, arr);

                        }

                    }

                }

​

                c++;

            }

​

            c = column == 0 ? 0 : column - 1;

            r++;

        }

    }

}

​

public class Counter

{

    public int Count(bool[, ] arr)

    {

        if (arr == null)

        {

            throw new ArgumentNullException(nameof(arr));

        }

​

        var islands = new List<List<Node>>();

        var rows = arr.GetLength(0);

        var columns = arr.GetLength(1);

        for (var i = 0; i < rows; i++)

        {

            for (var j = 0; j < columns; j++)

            {

                if (arr[i, j])

                {

                    var node = new Node()

                    {row = i, column = j};

                    //if node isn't already contained by an existing island

                    if (!islands.Any(isl => isl.Contains(node)))

                    {

                        var island = new List<Node>();

                        island.Add(node);

                        islands.Add(island);

                        node.AddNeighbors(island, arr);

                    }

                }

            }

        }

​

        return islands.Count;

    }

}

​

[TestFixture]

public class CounterTests

{

    protected Counter Counter

    {

        get;

        set;

    }

​

    [SetUp]

    public void SetUp()

    {

        Counter = new Counter();

    }

​

    [Test]

    public void Count_ThreeIslands_ReturnsExpected()

    {

        //00110010

        //10100000

        //10100000

        //01001010

        //00011100

        //00000000         

        var arr = new bool[, ]{{false, false, true, true, false, false, true, false}, {true, false, true, false, false, false, false, false}, {true, false, true, false, false, false, false, false}, {false, true, false, false, true, false, true, false}, {false, false, false, true, true, true, false, false}, {false, false, false, false, false, false, false, false}};

        Assert.AreEqual(3, Counter.Count(arr));

    }

​

    [Test]

    public void Count_SmallIslands_ReturnsExpected()

    {

        var arr = new bool[, ]{{false, false, true, false, false, true, false, false}, {true, false, false, false, false, false, false, true}, {false, false, true, false, true, false, false, false}, {true, false, false, false, false, false, true, false}, {false, false, true, false, false, false, false, false}, {false, false, false, false, true, false, false, false}};

        Assert.AreEqual(10, Counter.Count(arr));

    }

​

    [Test]

    public void Count_NoIslands_ReturnsExpected()

    {

        var arr = new bool[, ]{{false, false}, {false, false}};

        Assert.AreEqual(0, Counter.Count(arr));

    }

}