q13

q13.py

E = {
    "A": [],
    "B": ["A", "E"],
    "C": ["D", "H"],
    "D": ["B"],
    "E": ["F"],
    "F": [],
    "G": ["A"],
    "H": ["B", "G"],
}


class Toposort:
  def __init__(self):
    self.visited = []

  def DFS(self, node, graph):
    for x in graph.get(node, []):
      if x not in self.visited:
        self.DFS(x, graph)
    self.visited = [node] + self.visited

  def toposort(self, graph):
    for node in graph:
      if node not in self.visited:
        self.DFS(node, graph)
    return self.visited

if __name__ == "__main__":
  ts = Toposort()
  print(ts.toposort(E))