advent-of-code/2015/day-05/main.rb

87 lines
1.7 KiB
Ruby
Executable File

#!/usr/bin/env -S ruby
require "pathname"
require "set"
INPUTS = [
Pathname("inputs/test.txt"),
Pathname("inputs/puzzle.txt"),
].freeze
VOWELS = %[a e i o u].freeze
def vowel_count(input)
input.each_char.sum do |char|
VOWELS.include?(char) ? 1 : 0
end
end
def twin_letters(input)
input.each_char.each_cons(2).sum do |(char, next_char)|
char == next_char ? 1 : 0
end
end
def letter_pairs_count(input)
characters = input
.each_char
.each_cons(4)
.reject { |(a, b, c, d)| (a == b && b == c || b == c && c == d ) && a != d }
last_index = characters.size
pairs = characters
.flat_map
.with_index(1) { |(a, b, c, d), i| i == last_index ? [a+b, b+c, c+d] : [a+b] }
pairs.tally.values.max || 0
end
def surrounded_letter_count(input)
input
.each_char
.each_cons(3)
.count { |(a, _, b)| a == b }
end
def is_nice?(input)
return false if input.match?(/ab|cd|pq|xy/)
return false unless vowel_count(input) >= 3
return false unless twin_letters(input) >= 1
true
end
def is_really_nice?(input)
return false if letter_pairs_count(input) < 2
return false if surrounded_letter_count(input).zero?
true
end
def count_nice(file)
file.each_line.sum do |line|
line = line.chomp # chomp: true keyword argument emits warnings
next 0 if line.empty?
yield(line) ? 1 : 0
end
end
def solve_part_1(file)
nice_lines = count_nice(file) { |l| is_nice?(l) }
puts "\tThere are #{nice_lines} nice lines"
end
def solve_part_2(file)
nice_lines = count_nice(file) { |l| is_really_nice?(l) }
puts "\tThere are #{nice_lines} really nice lines"
end
def main(files)
files.each do |file|
puts "File: #{file}"
solve_part_1(file)
solve_part_2(file)
end
end
main(INPUTS)