2019: Day 7 Part 2

2019/day7/part2.rb

@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require_relative 'intcode'
+
+def inputter(queue)
+  idx = 0
+  proc do
+    input = queue[idx]
+    idx += 1
+    input
+  end
+end
+
+class Amplifier
+  def initialize(memory, phase)
+    @input_queue = [phase]
+    @computer = Intcode::Computer.new(memory) { @input_queue.shift }
+  end
+
+  def amplify(input)
+    @input_queue << input
+    output = nil
+    output = @computer.tick until output
+    output
+  end
+
+  def input(val)
+    @input_queue << val
+  end
+end
+
+def thrust(program, phases)
+  a = Amplifier.new(program.as_memory, phases[0])
+  b = Amplifier.new(program.as_memory, phases[1])
+  c = Amplifier.new(program.as_memory, phases[2])
+  d = Amplifier.new(program.as_memory, phases[3])
+  e = Amplifier.new(program.as_memory, phases[4])
+
+  cache = -Float::INFINITY
+  out1 = a.amplify(0)
+  loop do
+    out2 = b.amplify(out1)
+    out3 = c.amplify(out2)
+    out4 = d.amplify(out3)
+    out5 = e.amplify(out4)
+    return cache if out5 == :done_executing
+
+    cache = out5
+    out1 = a.amplify(out5)
+  end
+end
+
+program = Intcode.read(File.join(__dir__, 'input'))
+
+phase_space = [5, 6, 7, 8, 9].permutation(5)
+
+max_thrust = -Float::INFINITY
+max_phases = nil
+phase_space.each do |phases|
+  t = thrust(program, phases)
+  next unless t > max_thrust
+
+  max_thrust = t
+  max_phases = phases
+end
+
+pp max_phases
+puts max_thrust