Day 5

lib/day5/day5.ex

@@ -0,0 +1,205 @@
+defmodule Day5 do
+  def read_program do
+    File.read!("lib/day5/input.txt")
+    |> String.trim()
+    |> String.split(",")
+    |> Enum.map(&String.to_integer/1)
+  end
+
+  def run_program do
+    read_program()
+    |> run()
+  end
+
+  def test do
+    run([
+      3,
+      21,
+      1008,
+      21,
+      8,
+      20,
+      1005,
+      20,
+      22,
+      107,
+      8,
+      21,
+      20,
+      1006,
+      20,
+      31,
+      1106,
+      0,
+      36,
+      98,
+      0,
+      0,
+      1002,
+      21,
+      125,
+      20,
+      4,
+      20,
+      1105,
+      1,
+      46,
+      104,
+      999,
+      1105,
+      1,
+      46,
+      1101,
+      1000,
+      1,
+      20,
+      4,
+      20,
+      1105,
+      1,
+      46,
+      98,
+      99
+    ])
+  end
+
+  def run(memory, ip \\ 0)
+
+  def run(memory, ip) when ip < length(memory) do
+    IO.inspect(memory)
+
+    case eval(Enum.drop(memory, ip), memory) do
+      {memory, :halt} ->
+        memory
+
+      {memory, :cont, offset} ->
+        run(memory, ip + offset)
+
+      {memory, :jump, ip} ->
+        run(memory, ip)
+    end
+  end
+
+  def run(memory, _ip), do: memory
+
+  defmacro opcode(op, expected) do
+    quote do
+      rem(unquote(op), 100) == unquote(expected)
+    end
+  end
+
+  def get_param(op, param, val, memory) do
+    place = param + 2
+
+    if op |> div(pow(10, place)) |> rem(10) == 1 do
+      val
+    else
+      Enum.at(memory, val)
+    end
+  end
+
+  def pow(base, 1), do: base
+
+  def pow(base, exp) do
+    base * pow(base, exp - 1)
+  end
+
+  # halt
+  def eval([99 | _], memory) do
+    {memory, :halt}
+  end
+
+  # add
+  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)
+
+    {
+      List.replace_at(memory, dest, a_val + b_val),
+      :cont,
+      4
+    }
+  end
+
+  # multiply
+  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)
+
+    {
+      List.replace_at(memory, dest, a_val * b_val),
+      :cont,
+      4
+    }
+  end
+
+  # input
+  def eval([3, addr | _], memory) do
+    res = IO.gets("intcode> ") |> String.trim() |> String.to_integer()
+
+    {
+      List.replace_at(memory, addr, res),
+      :cont,
+      2
+    }
+  end
+
+  # output
+  def eval([op, param | _], memory) when opcode(op, 4) do
+    get_param(op, 0, param, memory) |> IO.inspect()
+
+    {memory, :cont, 2}
+  end
+
+  # jump if non-zero
+  def eval([op, condition, ip | _], memory) when opcode(op, 5) do
+    case get_param(op, 0, condition, memory) do
+      0 ->
+        {memory, :cont, 3}
+
+      _ ->
+        {memory, :jump, get_param(op, 1, ip, memory)}
+    end
+  end
+
+  # jump if zero
+  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)}
+
+      _ ->
+        {memory, :cont, 3}
+    end
+  end
+
+  # less than
+  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)
+
+    memory =
+      if a_val < b_val do
+        List.replace_at(memory, dest, 1)
+      else
+        List.replace_at(memory, dest, 0)
+      end
+
+    {memory, :cont, 4}
+  end
+
+  # equals
+  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)
+
+    memory =
+      if a_val == b_val do
+        List.replace_at(memory, dest, 1)
+      else
+        List.replace_at(memory, dest, 0)
+      end
+
+    {memory, :cont, 4}
+  end
+end

lib/day5/input.txt

@@ -0,0 +1 @@
+3,225,1,225,6,6,1100,1,238,225,104,0,2,171,209,224,1001,224,-1040,224,4,224,102,8,223,223,1001,224,4,224,1,223,224,223,102,65,102,224,101,-3575,224,224,4,224,102,8,223,223,101,2,224,224,1,223,224,223,1102,9,82,224,1001,224,-738,224,4,224,102,8,223,223,1001,224,2,224,1,223,224,223,1101,52,13,224,1001,224,-65,224,4,224,1002,223,8,223,1001,224,6,224,1,223,224,223,1102,82,55,225,1001,213,67,224,1001,224,-126,224,4,224,102,8,223,223,1001,224,7,224,1,223,224,223,1,217,202,224,1001,224,-68,224,4,224,1002,223,8,223,1001,224,1,224,1,224,223,223,1002,176,17,224,101,-595,224,224,4,224,102,8,223,223,101,2,224,224,1,224,223,223,1102,20,92,225,1102,80,35,225,101,21,205,224,1001,224,-84,224,4,224,1002,223,8,223,1001,224,1,224,1,224,223,223,1101,91,45,225,1102,63,5,225,1101,52,58,225,1102,59,63,225,1101,23,14,225,4,223,99,0,0,0,677,0,0,0,0,0,0,0,0,0,0,0,1105,0,99999,1105,227,247,1105,1,99999,1005,227,99999,1005,0,256,1105,1,99999,1106,227,99999,1106,0,265,1105,1,99999,1006,0,99999,1006,227,274,1105,1,99999,1105,1,280,1105,1,99999,1,225,225,225,1101,294,0,0,105,1,0,1105,1,99999,1106,0,300,1105,1,99999,1,225,225,225,1101,314,0,0,106,0,0,1105,1,99999,1008,677,677,224,1002,223,2,223,1006,224,329,101,1,223,223,1108,226,677,224,1002,223,2,223,1006,224,344,101,1,223,223,7,677,226,224,102,2,223,223,1006,224,359,1001,223,1,223,8,677,226,224,102,2,223,223,1005,224,374,1001,223,1,223,1107,677,226,224,102,2,223,223,1006,224,389,1001,223,1,223,1008,226,226,224,1002,223,2,223,1005,224,404,1001,223,1,223,7,226,677,224,102,2,223,223,1005,224,419,1001,223,1,223,1007,677,677,224,102,2,223,223,1006,224,434,1001,223,1,223,107,226,226,224,1002,223,2,223,1005,224,449,1001,223,1,223,1008,677,226,224,102,2,223,223,1006,224,464,1001,223,1,223,1007,677,226,224,1002,223,2,223,1005,224,479,1001,223,1,223,108,677,677,224,1002,223,2,223,1006,224,494,1001,223,1,223,108,226,226,224,1002,223,2,223,1006,224,509,101,1,223,223,8,226,677,224,102,2,223,223,1006,224,524,101,1,223,223,107,677,226,224,1002,223,2,223,1005,224,539,1001,223,1,223,8,226,226,224,102,2,223,223,1005,224,554,101,1,223,223,1108,677,226,224,102,2,223,223,1006,224,569,101,1,223,223,108,677,226,224,102,2,223,223,1006,224,584,1001,223,1,223,7,677,677,224,1002,223,2,223,1005,224,599,101,1,223,223,1007,226,226,224,102,2,223,223,1005,224,614,1001,223,1,223,1107,226,677,224,102,2,223,223,1006,224,629,101,1,223,223,1107,226,226,224,102,2,223,223,1005,224,644,1001,223,1,223,1108,677,677,224,1002,223,2,223,1005,224,659,101,1,223,223,107,677,677,224,1002,223,2,223,1006,224,674,1001,223,1,223,4,223,99,226