aboutsummaryrefslogtreecommitdiff
path: root/day04/part2
blob: 5127bb39062ac25d3e11006343f9c0a93972d9ed (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
#!/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