130 lines
4.0 KiB
Plaintext
130 lines
4.0 KiB
Plaintext
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# Advent of Code
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--- Day 6: Custom Customs ---
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As your flight approaches the regional airport where you'll switch to a much larger plane,
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customs declaration forms are distributed to the passengers.
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The form asks a series of 26 yes-or-no questions marked a through z. All you need to do is
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identify the questions for which anyone in your group answers "yes". Since your group is
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just you, this doesn't take very long.
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However, the person sitting next to you seems to be experiencing a language barrier and
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asks if you can help. For each of the people in their group, you write down the questions
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for which they answer "yes", one per line. For example:
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abcx
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abcy
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abcz
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In this group, there are 6 questions to which anyone answered "yes": a, b, c, x, y, and z.
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(Duplicate answers to the same question don't count extra; each question counts at most
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once.)
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Another group asks for your help, then another, and eventually you've collected answers
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from every group on the plane (your puzzle input). Each group's answers are separated by a
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blank line, and within each group, each person's answers are on a single line. For example:
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abc
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a
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b
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c
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ab
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ac
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a
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a
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a
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a
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b
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This list represents answers from five groups:
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• The first group contains one person who answered "yes" to 3 questions: a, b, and c.
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• The second group contains three people; combined, they answered "yes" to 3 questions:
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a, b, and c.
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• The third group contains two people; combined, they answered "yes" to 3 questions: a,
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b, and c.
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• The fourth group contains four people; combined, they answered "yes" to only 1
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question, a.
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• The last group contains one person who answered "yes" to only 1 question, b.
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In this example, the sum of these counts is 3 + 3 + 3 + 1 + 1 = 11.
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For each group, count the number of questions to which anyone answered "yes". What is the
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sum of those counts?
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Your puzzle answer was 6763.
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--- Part Two ---
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As you finish the last group's customs declaration, you notice that you misread one word in
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the instructions:
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You don't need to identify the questions to which anyone answered "yes"; you need to
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identify the questions to which everyone answered "yes"!
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Using the same example as above:
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abc
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a
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b
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c
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ab
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ac
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a
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a
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a
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a
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b
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This list represents answers from five groups:
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• In the first group, everyone (all 1 person) answered "yes" to 3 questions: a, b, and c.
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• In the second group, there is no question to which everyone answered "yes".
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• In the third group, everyone answered yes to only 1 question, a. Since some people did
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not answer "yes" to b or c, they don't count.
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• In the fourth group, everyone answered yes to only 1 question, a.
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• In the fifth group, everyone (all 1 person) answered "yes" to 1 question, b.
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In this example, the sum of these counts is 3 + 0 + 1 + 1 + 1 = 6.
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For each group, count the number of questions to which everyone answered "yes". What is the
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sum of those counts?
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Your puzzle answer was 3512.
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Both parts of this puzzle are complete! They provide two gold stars: **
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At this point, you should return to your Advent calendar and try another puzzle.
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If you still want to see it, you can get your puzzle input.
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References
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Visible links
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. https://adventofcode.com/
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. https://adventofcode.com/2020/about
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. https://adventofcode.com/2020/events
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. https://adventofcode.com/2020/settings
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. https://adventofcode.com/2020/auth/logout
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. Advent of Code Supporter
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https://adventofcode.com/2020/support
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. https://adventofcode.com/2020
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. https://adventofcode.com/2020
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. https://adventofcode.com/2020/support
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. https://adventofcode.com/2020/sponsors
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. https://adventofcode.com/2020/leaderboard
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. https://adventofcode.com/2020/stats
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. https://adventofcode.com/2020/sponsors
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. https://en.wikipedia.org/wiki/Customs_declaration
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. https://adventofcode.com/2020
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. https://adventofcode.com/2020/day/6/input
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