# --- Day 6: Custom Customs ---

# As your flight approaches the regional airport where you'll switch to a much
# larger plane, customs declaration forms are distributed to the passengers.

# The form asks a series of 26 yes-or-no questions marked a through z. All you
# need to do is identify the questions for which anyone in your group answers
# "yes". Since your group is just you, this doesn't take very long.

# However, the person sitting next to you seems to be experiencing a language
# barrier and asks if you can help. For each of the people in their group, you
# write down the questions for which they answer "yes", one per line. For
# example:

# abcx
# abcy
# abcz

# In this group, there are 6 questions to which anyone answered "yes": a, b, c,
# x, y, and z. (Duplicate answers to the same question don't count extra; each
# question counts at most once.)

# Another group asks for your help, then another, and eventually you've
# collected answers from every group on the plane (your puzzle input). Each
# group's answers are separated by a blank line, and within each group, each
# person's answers are on a single line. For example:

# abc

# a
# b
# c

# ab
# ac

# a
# a
# a
# a

# b

# This list represents answers from five groups:

#     The first group contains one person who answered "yes" to 3 questions: a,
# b, and c.
#     The second group contains three people; combined, they answered "yes" to
# 3 questions: a, b, and c.
#     The third group contains two people; combined, they answered "yes" to 3
# questions: a, b, and c.
#     The fourth group contains four people; combined, they answered "yes" to
# only 1 question, a.
#     The last group contains one person who answered "yes" to only 1 question,
# b.

# In this example, the sum of these counts is 3 + 3 + 3 + 1 + 1 = 11.

# For each group, count the number of questions to which anyone answered "yes".
# What is the sum of those counts?

with open("files/P6.txt", "r") as f:
    answers_groups = [line.split() for line in f.read().strip().split("\n\n")]


def part_1() -> None:
    counts: int = 0
    for answers_group in answers_groups:
        yes = len(
            set(
                [
                    answer
                    for individual_answers in answers_group
                    for answer in individual_answers
                ]
            )
        )
        counts += yes

    print(f"The sum of counts is {counts}")


# --- Part Two ---

# As you finish the last group's customs declaration, you notice that you
# misread one word in the instructions:

# You don't need to identify the questions to which anyone answered "yes"; you
# need to identify the questions to which everyone answered "yes"!

# Using the same example as above:

# abc

# a
# b
# c

# ab
# ac

# a
# a
# a
# a

# b

# This list represents answers from five groups:

#     In the first group, everyone (all 1 person) answered "yes" to 3
# questions: a, b, and c.
#     In the second group, there is no question to which everyone answered
# "yes".
#     In the third group, everyone answered yes to only 1 question, a. Since
# some people did not answer "yes" to b or c, they don't count.
#     In the fourth group, everyone answered yes to only 1 question, a.
#     In the fifth group, everyone (all 1 person) answered "yes" to 1 question,
# b.

# In this example, the sum of these counts is 3 + 0 + 1 + 1 + 1 = 6.

# For each group, count the number of questions to which everyone answered
# "yes". What is the sum of those counts?


def part_2() -> None:
    counts: int = 0
    for answers_group in answers_groups:
        yes = len(set.intersection(*map(set, answers_group)))
        counts += yes

    print(f"The sum of counts is {counts}")


if __name__ == "__main__":
    part_1()
    part_2()