aoc_omni/ruby/2019/4/lib/secure_container.rb
2025-12-06 08:01:55 -05:00

26 lines
884 B
Ruby

class Integer
def valid_part_1_password?
has_two_adjacent_digits? and digits_never_decrease?
end
def valid_part_2_password?
has_exactly_two_adjacent_digits? and digits_never_decrease?
end
def digits_never_decrease?
digits.reverse == digits.sort
end
def has_two_adjacent_digits?
digits[..-2].zip(digits[1..]).any? { |x, y| x == y }
end
def has_exactly_two_adjacent_digits?
threes = digits[..-3].zip(digits[1..-2]).zip(digits[2..]).map{ |x| x.flatten(1) }
triple_indices = threes.each_with_index.select{ |trip, index| trip[0] == trip[1] && trip[0] == trip[2] }.map(&:last)
pairs = digits[..-2].zip(digits[1..])
pair_indices = pairs.each_with_index.select{ |pair, index| pair[0] == pair[1]}.map(&:last)
pair_indices.any? { |pair_index| !triple_indices.include?(pair_index) && !triple_indices.include?(pair_index - 1) }
end
end