AoC Day 6 – Custom Customs

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

For each group, we can use a Bag to collect answers and the number of Bag keys will the number of questions that have received at least one "yes" answer.

my $input = slurp '6-input.txt';

my @groups = $input.split("\n\n");

say [+] @groups.map(*.comb(/\w/).Bag.keys.elems)

6416

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

In part two we can modify the Bag approach and count the number of entries that have a value equal to the number of people in the group.

  my $input = slurp '6-input.txt';

  my @groups = $input.split("\n\n");

  say [+] @groups.map(
      -> $g {
          my @people = $g.lines;
          @people.comb(/\w/).Bag.values.grep(-> $v { $v == @people.elems }).elems
      })

3050