[2024][ruby][13.x] refactored

2024/ruby/day_13.rb

@@ -5,60 +5,34 @@ gemfile do
   gem "z3"
 end
 
+require "z3"
+
 input = DATA.read
 
 machines = input.split("\n\n")
-  .map {|machine| machine.scan(/\d+/).map(&:to_i) }
-
-wins = ->(machine) {
-  ax, ay = machine[0,2]
-  bx, by = machine[2,2]
-  cx, cy = machine[4,2]
-
-  (0..cx/ax).filter_map {|a|
-    b = (cx - a * ax) / bx.to_f
-    if a * ax + b.to_i * bx == cx && a * ay + b.to_i * by == cy
-      [a, b.to_i]
-    else
-      nil
-    end
-  }.sort_by {|a,b| a + b }
-}
-
-pp machines.map { wins[_1].first }.compact.sum { 3 * _1 + _2 }
-
-require "z3"
-
-machines.each do |machine|
-  machine[4,2] = machine[4,2].map { _1 + 10_000_000_000_000 }
-end
+  .map {|machine| machine.scan(/\d+/).map(&:to_i).each_slice(2).to_a }
 
 def wins(machine)
-  return enum_for(__method__, machine) unless block_given?
-
-  ax, ay = machine[0,2]
-  bx, by = machine[2,2]
-  cx, cy = machine[4,2]
-
-  solutions = []
-  loop do
-    a = Z3.Int("a")
-    b = Z3.Int("b")
-    solver = Z3::Solver.new
-    solver.assert cx == a*ax + b*bx
-    solver.assert cy == a*ay + b*by
-    solutions.each do |a_s, b_s|
-      solver.assert a != a_s
-    end
-    return unless solver.satisfiable?
+  a = Z3.Int("a")
+  b = Z3.Int("b")
 
+  solver = Z3::Solver.new
+  machine.transpose.each do |a_, b_, c|
+    solver.assert a*a_ + b*b_ == c
+  end
+  if solver.satisfiable?
     model = solver.model
-    solutions << [model[a].to_i, model[b].to_i]
-    yield solutions.last
+    [a, b].map { model[_1].to_i }
+  else
+    nil
   end
 end
 
-pp machines.flat_map {|m| wins(m).sort_by { _1 + _2 } }.reject(&:empty?).sum { 3 * _1 + _2 }
+pp machines.map { wins(_1) }.compact.sum { 3 * _1 + _2 }
+
+pp machines
+  .map {|a,b,c| [a,b,c.map { _1 + 10_000_000_000_000 }] }
+  .map { wins(_1) }.compact.sum { 3 * _1 + _2 }
 
 __END__
 Button A: X+94, Y+34