# Input: lines like "<code>: <0 or 1>", then blank line,
#        then lines like "<code> (OR/AND/XOR) <code> -> <code>"
# Output: should result in
#           (2^0 * x00 + 2^1 * x01 + ...)
#         + (2^0 * y00 + 2^1 * y01 + ...)
#         = (2^0 * z00 + 2^1 * z01 + ...)
#         but four pairs of rules have their outputs swapped
#         output those eight outputs (sorted, joined by commas)

values = {}
rules = {}
z_values = []

found_blank_line = False
file = open("24_input.txt", "r")
for line in file:
  line = line.replace("\n", "")
  if line == "":
    found_blank_line = True
    continue
  if not found_blank_line:
    parts = line.split(": ")
    if parts[0][0] == "z":
      z_values.append(parts[0])
    continue
  parts = line.split(" -> ")
  rules[parts[0]] = parts[1]
  if parts[1][0] == "z":
    z_values.append(parts[1])

z_values = list(set(z_values))
z_values.sort()

for reference_z_value in z_values:
  z_index = reference_z_value[1:]
  values["x" + z_index] = 0
  values["y" + z_index] = 0
  sources = ["x" + z_index, "y" + z_index]
  new_rules = ["                  "] * 5
  while True:
    found_something = False
    remaining_rules = rules.copy()
    for rule in rules:
      parts = rule.split(" ")
      code1, operand, code2, result = parts[0], parts[1], parts[2], rules[rule]
      if code1 in values and code2 in values:
        if operand == "AND":
          values[result] = values[code1] & values[code2]
          if code1 in sources and code2 in sources:
            new_rules[3] = rule + " -> " + rules[rule]
          else:
            new_rules[2] = rule + " -> " + rules[rule]
        if operand == "OR":
          values[result] = values[code1] | values[code2]
          new_rules[4] = rule + " -> " + rules[rule]
        if operand == "XOR":
          values[result] = values[code1] ^ values[code2]
          if code1 in sources and code2 in sources:
            new_rules[0] = rule + " -> " + rules[rule]
          else:
            new_rules[1] = rule + " -> " + rules[rule]
        found_something = True
        del remaining_rules[rule]
    rules = remaining_rules
    if not found_something:
      print (new_rules)
      break