# 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.

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