58 lines
2.0 KiB
Python
58 lines
2.0 KiB
Python
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# SPDX-License-Identifier: MIT
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# Copyright (c) 2020 Akumatic
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#
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#https://adventofcode.com/2020/day/14
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def readFile() -> tuple:
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with open(f"{__file__.rstrip('code.py')}input.txt", "r") as f:
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return [line.strip().split(" = ") for line in f.readlines()]
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def recursive_floating_bits(value: int, idx: list) -> list:
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if len(idx) == 1:
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return [value | (1 << idx[0]), value & ~(1 << idx[0])]
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return recursive_floating_bits(value | (1 << idx[0]), idx[1:]) + \
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recursive_floating_bits(value & ~(1 << idx[0]), idx[1:])
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def mask_index(value: int, mask: str) -> list:
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# if bitmask bit is 1, memory address bit is overwritten with 1
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value |= int(mask.replace("X", "0"), 2)
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# take care of all floating bits
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positions = [35 - i for i, char in enumerate(mask) if char == "X"]
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return recursive_floating_bits(value, positions)
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def run_v2(input: list) -> dict:
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memory = dict()
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mask = None
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for instruction in input:
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if instruction[0] == "mask":
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mask = instruction[1]
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else: # instruction[0][:3] == "mem"
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value = int(instruction[1])
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indices = mask_index(int(instruction[0][4:-1]), mask)
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for idx in indices:
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memory[idx] = value
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return memory
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def run_v1(input: list) -> dict:
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mask_and, mask_or = None, None
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memory = dict()
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for instruction in input:
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if instruction[0] == "mask":
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mask_and = int(instruction[1].replace("X", "1"), 2)
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mask_or = int(instruction[1].replace("X", "0"), 2)
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else: # instruction[0][:3] == "mem"
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idx = int(instruction[0][4:-1])
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value = (int(instruction[1]) & mask_and) | mask_or
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memory[idx] = value
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return memory
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def part1(input: list) -> int:
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return sum(run_v1(input).values())
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def part2(input: list) -> int:
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return sum(run_v2(input).values())
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if __name__ == "__main__":
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input = readFile()
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print(f"Part 1: {part1(input)}")
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print(f"Part 2: {part2(input)}")
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