change directory names

18/4/main.rb

@@ -0,0 +1,88 @@
+require 'pry'
+
+events = []
+
+guards = {}
+
+File.open("input", "r") do |f|
+  f.each_line do |line|
+    events.push ({
+      date: line[/\d{4}-\d{2}-\d{2} \d{2}:\d{2}/],
+      type: (line.end_with?("shift\n") ? :begins_shift : (line.end_with?("asleep\n") ? :falls_asleep : :wakes_up)),
+      id: line[/#\d+/].to_s[1..-1].to_i
+    })
+  end
+end
+
+events.sort_by! do |event|
+  event[:date]
+end
+
+current_guard = 0
+begin_minute = 0
+
+events.each do |event|
+  if event[:type] == :begins_shift
+    if guards[event[:id]].nil?
+      guards[event[:id]] = Array.new(60){0}
+    end
+
+    current_guard = event[:id]
+  elsif event[:type] == :falls_asleep
+    begin_minute = event[:date][-2..-1].to_i
+  else
+    (event[:date][-2..-1].to_i - begin_minute).times do |minute|
+      guards[current_guard][begin_minute + minute] += 1
+    end
+  end
+end
+
+# Strategy 1
+
+sleepiest_guard = 0
+longest_time = 0
+
+guards.each do |id, counts|
+  time = counts.inject(:+)
+  if time > longest_time
+    longest_time = time
+    sleepiest_guard = id
+  end
+end
+
+sleepiest_minute = 0
+max_count = 0
+
+guards[sleepiest_guard].each_with_index do |count, index|
+  if count > max_count
+    max_count = count
+    sleepiest_minute = index
+  end
+end
+
+puts sleepiest_minute * sleepiest_guard
+
+# Strategy 2
+
+guard = 0
+minute = 0
+count = 0
+
+guards.each do |id, counts|
+  max_count = 0
+  max_index = 0
+  counts.each_with_index do |count_, index|
+    if count_ > max_count
+      max_count = count_
+      max_index = index
+    end
+  end
+
+  if max_count > count
+    guard = id
+    minute = max_index
+    count = max_count
+  end
+end
+
+puts guard * minute