#!/bin/env ruby

#part 1
ids = File.readlines('./input').map(&:strip)
checksum = {twos: 0, threes: 0}

chars = ids.map { |id| id.each_char.tally.delete_if { |char, count| count==1 }}
chars.each do |id|
    checksum[:twos] += 1 if id.has_value?(2)
    checksum[:threes] += 1 if id.has_value?(3)
end

puts checksum[:twos] * checksum[:threes]

#part 2
stop = false
count = 0
match = []
ids.each do |id|
    ids.each do |id2|
        next if id == id2
        count = 0
        id.each_char.with_index do |char, i|
            count += 1 if char != id2[i]
            break if count > 1
        end
        if count == 1
            puts id2
            match.push(id2)
            break
        end
    end
    if count ==1
        puts id
        match.push(id)
        break
    end
end

puts (match[0].chars & match[1].chars).join