#!/bin/env ruby

ids = []
File.readlines('./input').each do |line|
    line.strip!
    row = [0, 127]
    col = [0, 7]
    step = 64
    line[..6].each_char do |char|
        row[0] += step if char == 'B'
        row[1] -= step if char == 'F'
        step /= 2
    end
    step = 4
    line[-3..].each_char do |char|
        col[0] += step if char == 'R'
        col[1] -= step if char == 'L'
        step /= 2
    end
    id = (row[0] * 8) + col[0]
    ids.push(id)
    puts "Seat #{line} is at row #{row} and column #{col}. Seat id: #{id}"
end

puts "The highest seat ID is #{ids.max}"
ids.sort!
ids.each_index do |i|
    next if i == 0
    if ids[i] != (ids[i-1] + 1)
        puts "My seat is #{ids[i] - 1}"
        break
    end
end