07/1 - Ruby

Leo Silva Souza · Leo Silva Souza · commit 2955102c56a4 · 2018-12-07T17:48:38.000-02:00
diff --git a/2018/07_1/ruby/leovano.rb b/2018/07_1/ruby/leovano.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+input = File.readlines(ARGV[0])
+
+RULE = /^Step ([a-zA-Z]+) .* step ([a-zA-Z]+) can begin.$/.freeze
+input.map! { |line| line.match(RULE).captures }
+
+dependents = input.group_by(&:first).transform_values { |it| it.map(&:last) }
+dependencies = input.group_by(&:last).transform_values { |it| it.map(&:first) }
+
+dependents.default_proc = proc { |h, k| h[k] = [] }
+dependencies.default_proc = proc { |h, k| h[k] = [] }
+
+steps_done = []
+steps_current = dependents.keys.select { |k| dependencies[k].empty? }
+
+while steps_done.size < dependencies.size
+  steps_current.sort!
+
+  next_task = steps_current.find do |task|
+    (dependencies[task] - steps_done).empty?
+  end
+
+  steps_done << steps_current.delete(next_task)
+  steps_current += dependents[next_task]
+end
+
+puts steps_done.join
