get_graph_info

from collections import defaultdict


def get_true_adjacency_dict(adj_list):
    adjacency_dict = defaultdict(list)
    for a, b in adj_list:
        adjacency_dict[a].append(b)
        adjacency_dict[b].append(a)
    return dict(adjacency_dict)


def get_adjacency_matrix(adjacency_dict):
    def create_defaultdict_int():
        return defaultdict(int)

    adjacency_matrix = defaultdict(create_defaultdict_int)
    for node, linked_nodes in adjacency_dict.items():
        for linked_node in linked_nodes:
            adjacency_matrix[node][linked_node] += 1
        adjacency_matrix[node] = dict(adjacency_matrix[node])
    adjacency_matrix = dict(adjacency_matrix)
    return adjacency_matrix


def get_max_grade(adjacency_matrix):
    return sum(max(adjacency_matrix.values(), key=lambda x: sum(x.values())).values())


def count_loops(adjacency_matrix):
    return len([1 for node, linked_nodes in adjacency_matrix.items() if
                linked_nodes.get(node, 0) > 0])


def has_parallel(adjacency_matrix):
    for node, linked_nodes in adjacency_matrix.items():
        for linked_node, link_nbr in linked_nodes.items():
            if linked_node != node and link_nbr > 1:
                return True
    return False


def get_graph_info(adj_list):
    """
    >>> get_graph_info([[0,1],[2,3],[4,3]])
    (2, 0, False)
    >>> get_graph_info([[0,1],[0,1],[0,0],[2,3],[4,3]])
    (4, 1, True)
    >>> get_graph_info([[1, 3], [1, 4], [4, 5], [1, 3], [3, 2], [5, 2], [5, 5], [3, 4]])
    (4, 1, True)
    """
    adjacency_dict = get_true_adjacency_dict(adj_list)

    adjacency_matrix = get_adjacency_matrix(adjacency_dict)
    max_grade = get_max_grade(adjacency_matrix)
    loops_nbr = count_loops(adjacency_matrix)
    parallel = has_parallel(adjacency_matrix)
    return max_grade, loops_nbr, parallel