// function to add an edge to graph
public void addEdge(int u, int v, int weight)
{
AdjListNode node = new AdjListNode(v, weight);
adj[u].Add(node); // Add v to u's list
}
// A function used by shortestPath
public void topologicalSortUtil(int v, bool[] visited, Stack <int> stack)
{
// Mark the current node as visited
visited[v] = true;
// Recur for all the vertices adjacent to this vertex
foreach (var i in adj[v])
{
AdjListNode node = i;
if (!visited[node.vertex])
{
topologicalSortUtil(node.vertex, visited, stack);
}
}
stack.Push(v);
}