Day 7

lib/day5/day5.ex

@@ -8,11 +8,11 @@ defmodule Day5 do
 
   def run_program do
     read_program()
-    |> run()
+    |> run_cli()
   end
 
   def test do
-    run([
+    run_cli([
       3,
       21,
       1008,
@@ -63,27 +63,55 @@ defmodule Day5 do
     ])
   end
 
-  def run(memory, ip \\ 0)
+  def run_cli(memory) do
+    parent = self()
 
-  def run(memory, ip) when ip < length(memory) do
-    IO.puts("IP: #{ip}")
-    IO.inspect(memory)
+    proc =
+      spawn(fn ->
+        run(memory, parent)
+      end)
 
-    case eval(Enum.drop(memory, ip), memory) do
-      {_memory, :halt} ->
-        :halt
-
-      {memory, :cont, offset} ->
-        run(memory, ip + offset)
-
-      {memory, :jump, ip} ->
-        run(memory, ip)
-    end
-
-    :ok
+    Process.monitor(proc)
+    handle_cli_messages(proc)
   end
 
-  def run(memory, _ip), do: memory
+  def handle_cli_messages(proc) do
+    receive do
+      {:DOWN, _, _, _, _} ->
+        IO.puts("Exited")
+
+      {:in, _} ->
+        res = IO.gets("intcode> ") |> String.trim() |> String.to_integer()
+        send(proc, {:in, res})
+        handle_cli_messages(proc)
+
+      {:out, _, out} ->
+        IO.puts("Output: #{out}")
+        handle_cli_messages(proc)
+    end
+  end
+
+  def run(memory, parent, ip \\ 0)
+
+  def run(memory, parent, ip) when ip < length(memory) do
+    # IO.puts("IP: #{ip}")
+    # IO.inspect(memory)
+
+    case eval(Enum.drop(memory, ip), memory, parent) do
+      {memory, :halt} ->
+        send(parent, {:halt, self()})
+
+      {memory, :cont, offset} ->
+        run(memory, parent, ip + offset)
+
+      {memory, :jump, ip} ->
+        run(memory, parent, ip)
+    end
+  end
+
+  def run(memory, parent, _) do
+    send(parent, {:ok, self()})
+  end
 
   defmacro opcode(op, expected) do
     quote do
@@ -108,12 +136,12 @@ defmodule Day5 do
   end
 
   # halt
-  def eval([99 | _], memory) do
+  def eval([99 | _], memory, _) do
     {memory, :halt}
   end
 
   # add
-  def eval([op, a, b, dest | _], memory) when opcode(op, 1) do
+  def eval([op, a, b, dest | _], memory, _) when opcode(op, 1) do
     a_val = get_param(op, 0, a, memory)
     b_val = get_param(op, 1, b, memory)
 
@@ -125,7 +153,7 @@ defmodule Day5 do
   end
 
   # multiply
-  def eval([op, a, b, dest | _], memory) when opcode(op, 2) do
+  def eval([op, a, b, dest | _], memory, _) when opcode(op, 2) do
     a_val = get_param(op, 0, a, memory)
     b_val = get_param(op, 1, b, memory)
 
@@ -137,8 +165,13 @@ defmodule Day5 do
   end
 
   # input
-  def eval([3, addr | _], memory) do
-    res = IO.gets("intcode> ") |> String.trim() |> String.to_integer()
+  def eval([3, addr | _], memory, parent) do
+    send(parent, {:in, self()})
+
+    res =
+      receive do
+        {:in, val} -> val
+      end
 
     {
       List.replace_at(memory, addr, res),
@@ -148,15 +181,15 @@ defmodule Day5 do
   end
 
   # output
-  def eval([op, param | _], memory) when opcode(op, 4) do
+  def eval([op, param | _], memory, parent) when opcode(op, 4) do
     out = get_param(op, 0, param, memory)
-    IO.puts("Output: #{out}")
+    send(parent, {:out, self(), out})
 
     {memory, :cont, 2}
   end
 
   # jump if non-zero
-  def eval([op, condition, ip | _], memory) when opcode(op, 5) do
+  def eval([op, condition, ip | _], memory, _) when opcode(op, 5) do
     case get_param(op, 0, condition, memory) do
       0 ->
         {memory, :cont, 3}
@@ -167,7 +200,7 @@ defmodule Day5 do
   end
 
   # jump if zero
-  def eval([op, condition, ip | _], memory) when opcode(op, 6) do
+  def eval([op, condition, ip | _], memory, _) when opcode(op, 6) do
     case get_param(op, 0, condition, memory) do
       0 ->
         {memory, :jump, get_param(op, 1, ip, memory)}
@@ -178,7 +211,7 @@ defmodule Day5 do
   end
 
   # less than
-  def eval([op, a, b, dest | _], memory) when opcode(op, 7) do
+  def eval([op, a, b, dest | _], memory, _) when opcode(op, 7) do
     a_val = get_param(op, 0, a, memory)
     b_val = get_param(op, 1, b, memory)
 
@@ -193,7 +226,7 @@ defmodule Day5 do
   end
 
   # equals
-  def eval([op, a, b, dest | _], memory) when opcode(op, 8) do
+  def eval([op, a, b, dest | _], memory, _) when opcode(op, 8) do
     a_val = get_param(op, 0, a, memory)
     b_val = get_param(op, 1, b, memory)
 

lib/day7/day7.ex

@@ -0,0 +1,118 @@
+defmodule Day7 do
+  def part1 do
+    [0, 1, 2, 3, 4]
+    |> permutations()
+    |> Enum.map(fn digits -> {digits, test_inputs(digits)} end)
+    |> Enum.max_by(fn {_, out} -> out end)
+  end
+
+  def part2 do
+    [5, 6, 7, 8, 9]
+    |> permutations()
+    |> Enum.map(&test_looped/1)
+    |> Enum.max()
+  end
+
+  def test_inputs(digits) do
+    Enum.reduce(digits, 0, &run_amplifier/2)
+  end
+
+  def run_amplifier(phase_setting, prev_output) do
+    program = File.read!("lib/day7/input.txt") |> String.trim()
+    # program = "3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0"
+    # program = "3,23,3,24,1002,24,10,24,1002,23,-1,23,101,5,23,23,1,24,23,23,4,23,99,0,0"
+    # program =
+    # "3,31,3,32,1002,32,10,32,1001,31,-2,31,1007,31,0,33,1002,33,7,33,1,33,31,31,1,32,31,31,4,31,99,0,0,0"
+
+    program =
+      program
+      |> String.split(",")
+      |> Enum.map(&String.to_integer/1)
+
+    parent = self()
+
+    pid =
+      spawn(fn ->
+        Day5.run(program, parent)
+      end)
+
+    receive do
+      {:in, ^pid} -> send(pid, {:in, phase_setting})
+    end
+
+    receive do
+      {:in, ^pid} -> send(pid, {:in, prev_output})
+    end
+
+    receive do
+      {:out, ^pid, val} ->
+        val
+    end
+  end
+
+  def permutations([]), do: [[]]
+
+  def permutations(list) do
+    for x <- list, y <- permutations(list -- [x]), do: [x | y]
+  end
+
+  def test_looped(digits) do
+    digits
+    |> Enum.map(&start_amplifier/1)
+    # |> IO.inspect()
+    |> Stream.cycle()
+    |> Enum.reduce_while(0, fn pid, prev_output ->
+      case amplifier_step(pid, prev_output) do
+        :halt ->
+          {:halt, prev_output}
+
+        output ->
+          {:cont, output}
+      end
+    end)
+  end
+
+  def start_amplifier(phase_setting) do
+    program = File.read!("lib/day7/input.txt") |> String.trim()
+    # program =
+    #   "3,26,1001,26,-4,26,3,27,1002,27,2,27,1,27,26,27,4,27,1001,28,-1,28,1005,28,6,99,0,0,5"
+    # program =
+    #   "3,52,1001,52,-5,52,3,53,1,52,56,54,1007,54,5,55,1005,55,26,1001,54,-5,54,1105,1,12,1,53,54,53,1008,54,0,55,1001,55,1,55,2,53,55,53,4,53,1001,56,-1,56,1005,56,6,99,0,0,0,0,10"
+
+    program =
+      program
+      |> String.split(",")
+      |> Enum.map(&String.to_integer/1)
+
+    parent = self()
+
+    pid =
+      spawn(fn ->
+        Day5.run(program, parent)
+      end)
+
+    receive do
+      {:in, ^pid} -> send(pid, {:in, phase_setting})
+    end
+
+    pid
+  end
+
+  def amplifier_step(pid, prev_output) do
+    receive do
+      {:in, ^pid} ->
+        send(pid, {:in, prev_output})
+
+        receive do
+          {:out, ^pid, val} ->
+            val
+
+          {:halt, ^pid} ->
+            :halt
+        end
+
+      {:halt, ^pid} ->
+        :halt
+    end
+  end
+end

lib/day7/input.txt

@@ -0,0 +1 @@
+3,8,1001,8,10,8,105,1,0,0,21,42,67,88,101,114,195,276,357,438,99999,3,9,101,3,9,9,1002,9,4,9,1001,9,5,9,102,4,9,9,4,9,99,3,9,1001,9,3,9,1002,9,2,9,101,2,9,9,102,2,9,9,1001,9,5,9,4,9,99,3,9,102,4,9,9,1001,9,3,9,102,4,9,9,101,4,9,9,4,9,99,3,9,101,2,9,9,1002,9,3,9,4,9,99,3,9,101,4,9,9,1002,9,5,9,4,9,99,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,99,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,1,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,99,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,1,9,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,1,9,4,9,99,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,101,1,9,9,4,9,3,9,101,1,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,1,9,4,9,99,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,101,2,9,9,4,9,99