using System;

using System.Collections.Generic;

public class Graph

  {

private int[,] vertices;

public Graph(int[,] vertices)

​

      {

​

            this.vertices = vertices;

​

      }

public void AddEdge(int i, int j)

​

      {

​

            vertices[i,j] = 1;

​

      }

public void RemoveEdge(int i, int j)

​

      {

​

            vertices[i,j] = 0;

​

      }

public bool HasEdge(int i, int j)

​

      {

​

            return vertices[i,j] == 1;

​

      }

public IList<int> GetSuccessors(int i)

​

      {

​

            IList<int> successors = new List<int>();

​

​

            for (int j = 0; j < vertices.GetLength(1); j++)

​

            {

​

                  if (vertices[i,j] == 1)

​

                  {

​

                        successors.Add(j);

​

                  }

​

            }

​

​

            return successors;

​

      }

​

}