Solution to problem 6 in Python

src/P6.py

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+# --- 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:
+        q = len(
+            set(
+                [
+                    answer
+                    for individual_answers in answers_group
+                    for answer in individual_answers
+                ]
+            )
+        )
+        counts += q
+
+    print(f"The sum of counts is {counts}")
+
+
+if __name__ == "__main__":
+    part_1()