Add solution for 2015 day 14

2015/README.md

@@ -15,7 +15,7 @@
 | ✓      | 11  | Ruby
 | ✓      | 12  | Ruby
 | ✓      | 13  | Ruby
-|        | 14  |
+| ✓      | 14  | Ruby
 |        | 15  |
 |        | 16  |
 |        | 17  |

2015/day-14/.ruby-version

@@ -0,0 +1 @@
+3.0.0

2015/day-14/inputs/puzzle.txt

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+Rudolph can fly 22 km/s for 8 seconds, but then must rest for 165 seconds.
+Cupid can fly 8 km/s for 17 seconds, but then must rest for 114 seconds.
+Prancer can fly 18 km/s for 6 seconds, but then must rest for 103 seconds.
+Donner can fly 25 km/s for 6 seconds, but then must rest for 145 seconds.
+Dasher can fly 11 km/s for 12 seconds, but then must rest for 125 seconds.
+Comet can fly 21 km/s for 6 seconds, but then must rest for 121 seconds.
+Blitzen can fly 18 km/s for 3 seconds, but then must rest for 50 seconds.
+Vixen can fly 20 km/s for 4 seconds, but then must rest for 75 seconds.
+Dancer can fly 7 km/s for 20 seconds, but then must rest for 119 seconds.

2015/day-14/inputs/test.txt

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+Comet can fly 14 km/s for 10 seconds, but then must rest for 127 seconds.
+Dancer can fly 16 km/s for 11 seconds, but then must rest for 162 seconds.

2015/day-14/main.rb

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+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "pathname"
+
+Item = Struct.new(:name, :speed, :active_time, :recovery_time)
+
+def parse_file(file)
+  file.each_line.map do |line|
+    line.partition(" can fly ") => [name, _, tail]
+    tail.partition(" km/s for ") => [speed, _, tail]
+    tail.partition(" seconds, but then must rest for ") => [active_time, _, tail]
+    tail.split.first => recovery_time
+    Item.new(name, speed.to_i, active_time.to_i, recovery_time.to_i)
+  end
+end
+
+def race(items, time)
+  active_times = items.map { |i| [i, 1..i.active_time] }.to_h
+
+  (1..time).each_with_object(items.map {|i| [i, {score: 0, distance: 0}] }.to_h) do |sec, stats|
+    stats.each do |item, stat|
+      active = active_times[item]
+
+      stat[:distance] += item.speed if active.include?(sec)
+
+      next unless sec > active.last
+
+      active_start = sec + item.recovery_time
+      active_end = active_start - 1 + item.active_time
+      active_times[item] = active_start..active_end
+    end
+
+    leading = stats.values.max_by { |v| v[:distance] }[:distance]
+    stats.each do |n, s|
+      s[:score] += 1 if s[:distance] == leading
+    end
+  end
+end
+
+def main(file_paths)
+  file_paths.each do |file_path|
+    puts "File: #{file_path}"
+    items = parse_file(file_path)
+
+    results = race(items, 2503)
+
+    results.values.max_by { |v| v[:distance] } => {distance:}
+    puts "solution 1: #{distance}"
+
+    results.values.max_by { |v| v[:score] } => {score:}
+    puts "solution 2: #{score}"
+  end
+end
+
+main(ARGV.map { |x| Pathname(x) })