using System;

public class Program

{

    public static void Main()

    {

        var graph = CreateGraph();

​

        Flow(graph);

    }

​

    private static void Flow(G glass)

    {

        Out($" Flowing into glass {glass.Id}...");

​

        var isWaterEscaping = false;

​

        if (glass.Pipes is object)

        {

            foreach (var pipe in glass.Pipes)

            {

                if (!isWaterEscaping)

                {

                    Out($" Flowing into pipe {pipe.Id}...");

​

                    if (!pipe.IsFull && !pipe.StartBlocked)

                    {

                        if (pipe.EndBlocked || pipe.Glass.IsFull)

                        {

                            Out($"Filled pipe {pipe.Id}");

                            pipe.IsFull = true;

                        }

                        else

                        {

                            Flow(pipe.Glass);

                            isWaterEscaping = true;

                        }

                    }

                    else if (pipe.StartBlocked)

                    {

                        Out($"  Can't fill pipe {pipe.Id} as start blocked...");

                    }

                }

            }

        }

​

        if (!isWaterEscaping)

        {

            Out($"Filled glass {glass.Id}");

            glass.IsFull = true;

        }

    }

​

    private static void Out(string value)

    {

        Console.WriteLine(value);

    }

​

    private static G CreateGraph()

    {

        return new G(1)

        {

            Pipes = new[]

            {

                new P(3)

                {

                    Glass = new G(3)

                    {

                        Pipes = new []

                        {

                            new P(7)

                            {

                                Glass = new G(7),

                                StartBlocked = true

                            },

                            new P(6)

                            {

                                Glass = new G(6),

                                EndBlocked = true

                            }

                        }

                    }

                },

                new P(2)

                {

                    Glass = new G(2)

                    {

                        Pipes = new []

                        {

                            new P(5)

                            {

                                Glass = new G(5),

                                StartBlocked = true

                            },

                            new P(4)

                            {

                                Glass = new G(4)

                            }

                        }

                    }

                }

            }

        };

    }

    class G

    {

        public P[] Pipes;

        public bool IsFull;

        public int Id;

​

        public G(int id)

        {

            Id = id;

        }

    }

​

    class P

    {

        public G Glass;

        public bool StartBlocked;

        public bool EndBlocked;

        public bool IsFull;

        public int Id;

​

        public P(int id)

        {

            Id = id;

        }

    }

}