advent-of-code/2017/d18/ex1/ex1.py

76 lines
1.9 KiB
Python
Executable file

#!/usr/bin/env python
import collections
import enum
import sys
from typing import NamedTuple
class Op(enum.StrEnum):
SND = "snd"
SET = "set"
ADD = "add"
MUL = "mul"
MOD = "mod"
RCV = "rcv"
JGZ = "jgz"
class Instruction(NamedTuple):
op: Op
x: str
y: str | None = None
@classmethod
def from_str(cls, input: str) -> "Instruction":
op, *rest = input.split()
return cls(Op(op), *rest)
def solve(input: str) -> int:
def parse(input: str) -> list[Instruction]:
return [Instruction.from_str(line) for line in input.splitlines()]
def resolve(y: str | None, registers: dict[str, int]) -> int:
assert y is not None # Sanity check
try:
return int(y)
except ValueError:
return registers[y]
instructions = parse(input)
registers: dict[str, int] = collections.defaultdict(int)
ip = 0
freq: int | None = None
while True:
assert 0 <= ip < len(instructions) # Sanity check
instr = instructions[ip]
ip += 1
match instr.op:
case Op.SND:
freq = resolve(instr.x, registers)
case Op.SET:
registers[instr.x] = resolve(instr.y, registers)
case Op.ADD:
registers[instr.x] += resolve(instr.y, registers)
case Op.MUL:
registers[instr.x] *= resolve(instr.y, registers)
case Op.MOD:
registers[instr.x] %= resolve(instr.y, registers)
case Op.RCV:
if resolve(instr.x, registers) != 0:
assert freq is not None
return freq
case Op.JGZ:
if resolve(instr.x, registers) > 0:
ip += resolve(instr.y, registers) - 1 # Account auto-increment
def main() -> None:
input = sys.stdin.read()
print(solve(input))
if __name__ == "__main__":
main()