DFS(graph, start_node, end_node):

    frontier = new Stack()

    frontier.push(start_node)

    explored = new Set()    while frontier is not empty:

        current_node = frontier.pop()

        if current_node in explored: continue

        if current_node == end_node: return success

        for neighbor in graph.get_neigbhors(current_node):

            frontier.push(neighbor)        explored.add(current_node)