# give a class Person with find_father() / find_mother() methods
# determine if two person has common parent (blood relation)
def has_common_parent(person_a, person_b):
    # NP hard, just use two sets to find common parent
    pass

# give a class Person with find_father() / find_mother() methods
# determine if two person has common parent (blood relation)
def has_common_parent(person_a, person_b):
    # NP hard, just use two sets to find common parent
    pass

# give a class Person with find_father() / find_mother() methods # determine if two person has common parent (blood relation) # NP hard, just use two sets to find common parent