Advent Of Code 2020 Day 6: Game, Sets, Match

The Day 6 puzzle is trivially solved using sets. The input is a list of groups, and the answers given by each member of each group, like so:

a
b
c

ab
ac

Part 1 asks for the sum of unique answers in each group. This is the set union of each group. Python sets have a handy union operator:

    p1 = 0
    for group in groups:
        c = set()
        for person in group:
            c |= set(person)
        p1 += len(c)

Part 2 asks for the sum of answers given by all members of each group. This is the set intersection, and Python has an operator for that, too!

    p2 = 0
    for group in groups:
        c = set(string.ascii_lowercase)
        for person in group:
            c &= set(person)
        p2 += len(c)