#!/usr/bin/env ruby input = $stdin.readlines.map(&:chomp).sort currentguard = nil guards = Hash.new { |h,k| h[k] = Hash.new { |h,k| h[k] = Array.new(60, false) } } (0...input.length).each do |i| if input[i] =~ /\[1518-\d\d-\d\d \d\d:\d\d\] Guard #(\d+) begins shift/ currentguard = $1.to_i elsif input[i] =~ /\[1518-(\d\d-\d\d) \d\d:(\d\d)\] falls asleep/ date = $1 smin = $2.to_i input[i+1] =~ /\[1518-\d\d-\d\d \d\d:(\d\d)\] wakes up/ emin = $1.to_i (smin...emin).each do |m| guards[currentguard][date][m] = true end else next end end sleepiestguard = nil maxmin = 0 guards.each do |id, days| minutes = Array.new(60, 0) (0...60).each do |m| days.each_value do |mins| minutes[m] += 1 if mins[m] end end if minutes.max > maxmin maxmin = minutes.max sleepiestguard = id end end minutes = Array.new(60, 0) (0...60).each do |m| guards[sleepiestguard].each_value do |mins| minutes[m] += 1 if mins[m] end end sleepiestminute = minutes.index(minutes.max) puts sleepiestguard * sleepiestminute