using System using System Collections Generic using System Linq using

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

namespace ConsoleApplication7
{
    class Program
    {
        static void Main(string[] args)
        {
            const int edge_count = 5;
            int head_count = 4;

           int[] edge_start = new int[edge_count] {1,0,3,0,3};
           int[] edge_end = new int[edge_count] {2,3,1,1,2};

           //int[] head_list = new int[head_count];
           //int[] list_list = new int[edge_count];

           int[] rez = new int[edge_start.Length+1];

           for (int i = 0; i < edge_start.Length; i++)
           {
               rez[edge_start[i]+1]++;
               
           }

           for (int i = 1; i < rez.Length; i++)
           {
               rez[i] = rez[i] + rez[i - 1];
           }

           int[] sorted_edge_start = new int[edge_count];
           int[] sorted_edge_end = new int[edge_count];

           for (int i = 0; i < edge_start.Length; i++)
           {
               int offset = rez[edge_start[i]];
               rez[edge_start[i]]++;
               sorted_edge_start[offset] = edge_start[i];
               sorted_edge_end[offset] = edge_end[i];
           }
           int z = 0;
           
        }
    }
}