diff --git a/2022/day20.py b/2022/day20.py index bcf7939..80f6411 100644 --- a/2022/day20.py +++ b/2022/day20.py @@ -5,15 +5,17 @@ import sys class Number: index: int + current: int value: int def __init__(self, index: int, value: int): self.index = index + self.current = index self.value = value def __eq__(self, other): if isinstance(other, Number): - return self.index == other.index + return self.value == other.value elif isinstance(other, int): return self.value == other return False @@ -32,29 +34,37 @@ def decrypt(numbers: list[Number], key: int, rounds: int) -> int: numbers = numbers.copy() original = numbers.copy() - numbers2index = {number: number.index for number in numbers} - def swap(lhs: Number, rhs: Number): - i1, i2 = numbers2index[lhs], numbers2index[rhs] - numbers[i1], numbers[i2] = numbers[i2], numbers[i1] - numbers2index[lhs], numbers2index[rhs] = i2, i1 - - def move(index: int, value: int): - assert value >= 0 - while value > 0: - if index == len(numbers) - 1: - swap(numbers[0], numbers[-1]) - index, value = 0, value - 1 - else: - swap(numbers[index + 1], numbers[index]) - index, value = index + 1, value - 1 + for number in numbers: + number.current = number.index for _ in range(rounds): for number in original: - index = numbers2index[number] - move(index, (number.value * key) % (len(numbers) - 1)) + index = number.current + offset = (number.value * key) % (len(numbers) - 1) + target = index + offset - index_of_0 = numbers.index(0) + # need to wrap + if target >= len(numbers): + for number_2 in numbers[:index]: + number_2.current += 1 + numbers = [number] + numbers[:index] + numbers[index + 1 :] + + target = offset - (len(numbers) - index) + 1 + index = 0 + + for number_2 in numbers[index : target + 1]: + number_2.current -= 1 + + number.current = target + numbers = ( + numbers[:index] + + numbers[index + 1 : target + 1] + + [number] + + numbers[target + 1 :] + ) + + index_of_0 = numbers.index(0) # type: ignore return sum( numbers[(index_of_0 + offset) % len(numbers)].value * key for offset in (1000, 2000, 3000)