diff --git a/2018/day16.py b/2018/day16.py
index 1a52d25..d0734b6 100644
--- a/2018/day16.py
+++ b/2018/day16.py
@@ -6,46 +6,40 @@ import re
 numbers_pt1 = [[int(s) for s in re.findall(r'-?\d+', d)] for d in data if d]
 numbers_pt2 = [[int(s) for s in re.findall(r'-?\d+', d)] for d in data2 if d]
 
-def oper_prototype(operator, immediate_a, immediate_b, regs, opcodes):
-  op, a, b, c = opcodes
-  r = list(regs)
-  r[c] = operator((a if immediate_a else regs[a]), (b if immediate_b else regs[b]))
-  return r
 
-addr = lambda regs, opcodes: oper_prototype(int.__add__, False, False, regs, opcodes)
-addi = lambda regs, opcodes: oper_prototype(int.__add__, False, True, regs, opcodes)
-mulr = lambda regs, opcodes: oper_prototype(int.__mul__, False, False, regs, opcodes)
-muli = lambda regs, opcodes: oper_prototype(int.__mul__, False, True, regs, opcodes)
-andr = lambda regs, opcodes: oper_prototype(int.__and__, False, False, regs, opcodes)
-andi = lambda regs, opcodes: oper_prototype(int.__and__, False, True, regs, opcodes)
-orr = lambda regs, opcodes: oper_prototype(int.__or__, False, False, regs, opcodes)
-ori = lambda regs, opcodes: oper_prototype(int.__or__, False, True, regs, opcodes)
-setr = lambda regs, opcodes: oper_prototype(lambda a, b: a, True, True, regs, opcodes)
-seti = lambda regs, opcodes: oper_prototype(lambda a, b: a, False, True, regs, opcodes)
-gtir = lambda regs, opcodes: oper_prototype(int.__gt__, True, False, regs, opcodes)
-gtri = lambda regs, opcodes: oper_prototype(int.__gt__, False, True, regs, opcodes)
-gtrr = lambda regs, opcodes: oper_prototype(int.__gt__, False, False, regs, opcodes)
-eqir = lambda regs, opcodes: oper_prototype(int.__eq__, True, False, regs, opcodes)
-eqri = lambda regs, opcodes: oper_prototype(int.__eq__, False, True, regs, opcodes)
-eqrr = lambda regs, opcodes: oper_prototype(int.__eq__, False, False, regs, opcodes)
+class oper_factory:
+  def __init__(self, operator, immediate_a, immediate_b):
+    self.operator = operator
+    self.immediate_a = immediate_a
+    self.immediate_b = immediate_b
+
+  def __call__(self, regs, opcodes):
+    op, a, b, c = opcodes
+    r = list(regs)
+    r[c] = self.operator((a if self.immediate_a else regs[a]), (b if self.immediate_b else regs[b]))
+    return r
+
+bin_ops = (int.__add__, int.__mul__, int.__and__, int.__or__)
+set_op = lambda a, b: a  # Just discard second operand
+comp_ops = (int.__gt__, int.__eq__)
+comp_imms = ((True, False), (False, True), (False, False))  # ir, ri, rr
+
+instructions = [oper_factory(op, False, imm) for op in bin_ops for imm in (False, True)] \
+             + [oper_factory(set_op, imm, True) for imm in (False, True)] \
+             + [oper_factory(op, *imm) for op in comp_ops for imm in comp_imms]
 
-instructions = [addr, addi, mulr, muli, andr, andi, orr, ori, setr, seti, gtir, gtri, gtrr, eqir, eqri, eqrr]
 
 num_3_or_more = 0
 instruction_codes = {}
-instruction_impossibilities = {}
 for before, opcodes, after in zip(numbers_pt1[::3], numbers_pt1[1::3], numbers_pt1[2::3]):
   possibilities = set()
-  impossibilities = set()
   for op in instructions:
     try:
       r2 = op(before, opcodes)
       if r2 == after:
         possibilities.add(op)
-      else:
-        impossibilities.add(op)
-    except:
-      impossibilities.add(op)
+    except Exception:
+      pass
   if len(possibilities) >= 3:
     num_3_or_more += 1
 
@@ -54,28 +48,20 @@ for before, opcodes, after in zip(numbers_pt1[::3], numbers_pt1[1::3], numbers_p
   else:
     instruction_codes[opcodes[0]] = set(possibilities)
 
-  if opcodes[0] in instruction_impossibilities:
-    instruction_impossibilities[opcodes[0]] |= impossibilities
-  else:
-    instruction_impossibilities[opcodes[0]] = set(impossibilities)
-
 print(num_3_or_more)  # Part 1
 
-for k in instruction_codes:
-  instruction_codes[k] -= instruction_impossibilities[k]
 while sum([len(i) for i in instruction_codes.values()]) > len(instructions):
-  for code, cands in instruction_codes.items():
-    if len(cands) == 1:
+  for code, candidates in instruction_codes.items():
+    if len(candidates) == 1:
       for code2 in [c for c in instruction_codes if c != code]:
-        instruction_codes[code2] -= cands
-
-opcode_convert = {code: list(s)[0] for code, s in instruction_codes.items()}
+        instruction_codes[code2] -= candidates
+instruction_codes = {k: tuple(s)[0] for k, s in instruction_codes.items()}
 
 regs = [0, 0, 0, 0]
 for i, opcodes in enumerate(numbers_pt2):
   try:
-    regs = opcode_convert[opcodes[0]](regs, opcodes)
-  except:
+    regs = instruction_codes[opcodes[0]](regs, opcodes)
+  except Exception:
     print(f'Line {i}: {regs}  {opcodes}')
     raise