130 lines
4.0 KiB
Plaintext
130 lines
4.0 KiB
Plaintext
# Advent of Code
|
||
|
||
--- 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?
|
||
|
||
Your puzzle answer was 6763.
|
||
|
||
--- 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?
|
||
|
||
Your puzzle answer was 3512.
|
||
|
||
Both parts of this puzzle are complete! They provide two gold stars: **
|
||
|
||
At this point, you should return to your Advent calendar and try another puzzle.
|
||
|
||
If you still want to see it, you can get your puzzle input.
|
||
|
||
References
|
||
|
||
Visible links
|
||
. https://adventofcode.com/
|
||
. https://adventofcode.com/2020/about
|
||
. https://adventofcode.com/2020/events
|
||
. https://adventofcode.com/2020/settings
|
||
. https://adventofcode.com/2020/auth/logout
|
||
. Advent of Code Supporter
|
||
https://adventofcode.com/2020/support
|
||
. https://adventofcode.com/2020
|
||
. https://adventofcode.com/2020
|
||
. https://adventofcode.com/2020/support
|
||
. https://adventofcode.com/2020/sponsors
|
||
. https://adventofcode.com/2020/leaderboard
|
||
. https://adventofcode.com/2020/stats
|
||
. https://adventofcode.com/2020/sponsors
|
||
. https://en.wikipedia.org/wiki/Customs_declaration
|
||
. https://adventofcode.com/2020
|
||
. https://adventofcode.com/2020/day/6/input
|