[10:49] Ivan Gocevski | PROLAN

using System;
using System.Collections.Generic;
using System.Linq;


namespace CrackTheCode2
{
    public class Coordinate
    {
        public int x;
        public int y;


        public Coordinate(int x, int y)
        {
            this.x = x;
            this.y = y;
        }


        public string ShowCoordinates()
        {
            return x + ":" + y;
        }
    }


    public class List : List<Coordinate>
    {
    }
    class Program
    {
        static void Main(string[] args)
        {
            string input = System.IO.File.ReadAllText(@"crack-the-code-2_input.txt");
            //string input = "4:4,4:2,2:4,2:2,4:6,2:6";


            List<string> list = new List<string>(input.Split(','));
            List<Coordinate> coordinatesList = new List();
            int count = 0;


            //list = list.Distinct().ToList();
            list.ForEach(item => coordinatesList.Add(new Coordinate(
                x: int.Parse(item.Substring(0, item.IndexOf(':'))),
                y: int.Parse(item.Substring(item.IndexOf(':') + 1)))));
            coordinatesList = coordinatesList.OrderBy(item => item.x).ThenBy(item => item.y).ToList();

            List<string> added = new List<string>();


            for (int A = 0; A < coordinatesList.Count; A++)
            {
                for (int B = A + 1; B < coordinatesList.Count; B++)
                {
                    if (IsPerpendicularABx(coordinatesList[A], coordinatesList[B]))
                    {
                        for (int C = B + 1; C < coordinatesList.Count; C++)
                        {
                            if (IsPerpendicularACy(coordinatesList[A], coordinatesList[C]))
                            {
                                for (int D = C + 1; D < coordinatesList.Count; D++)
                                {
                                    if (IsRectangleABCD(coordinatesList[B], coordinatesList[C], coordinatesList[D]))
                                    {
                                        count++;
                                        added.Add(coordinatesList[A].ShowCoordinates() + " + " +
                                            coordinatesList[B].ShowCoordinates() + " + " +
                                            coordinatesList[C].ShowCoordinates() + " + " +
                                            coordinatesList[D].ShowCoordinates());
                                    }
                                }
                            }
                        }
                    }
                }
            }


            Console.WriteLine(count);
        }
        private static bool IsPerpendicularABx(Coordinate A, Coordinate B)
        {
            if (A.x == B.x)
            {
                return true;
            }


            return false;
        }


        private static bool IsPerpendicularACy(Coordinate A, Coordinate C)
        {
            if (A.y == C.y)
            {
                return true;
            }


            return false;
        }


        private static bool IsRectangleABCD(Coordinate B, Coordinate C, Coordinate D)
        {
            if (B.y == D.y && C.x == D.x)
            {
                return true;
            }


            return false;
        }
    }
}