def __init__(self, flow_network):
        self.flow_network = flow_network
        self.verticies_count = flow_network.verticesCount
        self.source_index = flow_network.sourceIndex
        self.sink_index = flow_network.sinkIndex
        # it's just a reference, so you shouldn't change
        # it in your algorithms, use deep copy before doing that
        self.graph = flow_network.graph
        self.executed = False