def create_data_model(distance_matrix):
    """Stores the data for the problem."""
    data = {}
    data['distance_matrix'] = distance_matrix
    data['num_vehicles'] = 1 #The number of vehicles in the problem, which is 1 because this is a TSP. For general routing problems, the number of vehicles can be greater than 1.
    data['depot'] = 0  # 起點，the starting location for the route. In this case, the depot is 0, which corresponds to New York City.
    return data