using System using System Collections Generic using System Linq using

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace test
{
    class Graph
    {
        private int[] I;
        private int[] J;
        private int[] H;
        private int[] L;
        public Graph(int[] iI, int[] jJ)
        {
            I = iI;
            J = jJ;
            H = new int[1];
            L = new int[1];
        }
        public void Add(int start, int end)
        {

            Array.Resize(ref I, I.Length + 1);
            Array.Resize(ref J, J.Length + 1);
            I[I.Length - 1] = start;
            J[J.Length - 1] = end;

        }
        public void printListOfArcs()
        {
            for (int i = 0; i < I.Length; i++)
            {
                Console.WriteLine("дуга из-в {0}-{1}", I[i], J[i]);   
            }
        }
         public int CountNodes()
        {
            int nodesCount = 0;
            var hashSet = new HashSet<int>();//Создаём объект типа множество
            for (int i = 0; i < I.Length; i++)
            {
                if (!hashSet.Contains(I[i]))
                {
                    hashSet.Add(I[i]);// Проходимся по массиву и добавляем только те элементы, которых во множестве ещё нет
                    nodesCount++;
                }

                if (!hashSet.Contains(J[i]))
                {
                    hashSet.Add(J[i]);
                    nodesCount++;
                }
            }

            return nodesCount;


        }
        public void BuildArcsBeamsList()
        {
            Array.Resize(ref H, CountNodes());
            Array.Resize(ref L, I.Length);
            for (int h = 0; h < CountNodes(); h++)
            {
                H[h] = -1;
            }
            for (int l = 0; l < CountNodes(); l++)
            {
                H[l] = -1;
            }
            int i;
            for (int k = 0; k < I.Length; k++)
            {
                i = I[k];
                L[k] = H[i];
                H[i] = k;
            }
        }
        public void PrintIJHL()
        {
            BuildArcsBeamsList();
            Console.WriteLine("I:     J:     H:     L:");
            for (int i = 0; i < I.Length; i++)
            {
                if (i < H.Length)
                    Console.WriteLine("{0}      {1}      {2}      {3}", I[i], J[i], H[i], L[i]);
                else
                    Console.WriteLine("{0}      {1}              {2}", I[i], J[i], L[i]);
            }
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            var startArc = new int[] { 0, 1, 2 };
            var endArc = new int[] { 1, 2, 3 };
            var graph = new Graph(startArc, endArc);
            graph.Add(1, 3);
            graph.Add(0, 2 );
            graph.printListOfArcs();
            int a = graph.CountNodes();
            Console.WriteLine(a);
            graph.PrintIJHL();
            Console.ReadKey();
        }
    }
}