67 lines
1.6 KiB
Python
Executable file
67 lines
1.6 KiB
Python
Executable file
#!/usr/bin/env python
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import collections
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import enum
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import sys
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from typing import NamedTuple
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class Op(enum.StrEnum):
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CPY = "cpy"
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INC = "inc"
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DEC = "dec"
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JNZ = "jnz"
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class Instruction(NamedTuple):
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op: Op
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x: str
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y: str | None = None
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@classmethod
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def from_str(cls, input: str) -> "Instruction":
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op, *rest = input.split()
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return cls(Op(op), *rest)
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def solve(input: str) -> int:
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def parse(input: str) -> list[Instruction]:
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return [Instruction.from_str(line) for line in input.splitlines()]
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def resolve(y: str | None, registers: dict[str, int]) -> int:
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assert y is not None # Sanity check
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try:
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return int(y)
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except ValueError:
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return registers[y]
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instructions = parse(input)
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registers: dict[str, int] = collections.defaultdict(int)
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ip = 0
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while True:
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if ip < 0 or ip >= len(instructions):
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break
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instr = instructions[ip]
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ip += 1
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match instr.op:
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case Op.CPY:
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assert instr.y is not None
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registers[instr.y] = resolve(instr.x, registers)
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case Op.INC:
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registers[instr.x] += 1
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case Op.DEC:
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registers[instr.x] -= 1
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case Op.JNZ:
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if resolve(instr.x, registers) != 0:
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ip += resolve(instr.y, registers) - 1 # Account auto-increment
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return registers["a"]
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def main() -> None:
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input = sys.stdin.read()
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print(solve(input))
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if __name__ == "__main__":
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main()
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