using System;//zad.2/125str

using System.Collections.Generic;

​

public class Program

{

    public static void DFS(int n, List<int>[] G, List <int> T, int r) 

    { int x, y, i, k; 

bool[] used = new bool[n + 1];

     Stack<int> S = new Stack<int>();

     for (i = 1; i <= n; i++) 

         used[i] =false;

     S.Push(r); used[r] = true; T[r]=0;

     while (S.Count > 0) 

     { x = S.Peek(); k = G[x].Count; 

if (k > 0)

{ y = G[x][k - 1]; G[x].RеmоvеAt (k - 1); 

if (!used[y])

{ used [y] = true; T[y] = x; S.Push(y); } 

}

else S.Pop(); 

​

​

    }

}

}