71 lines
1.8 KiB
Python
71 lines
1.8 KiB
Python
# -*- encoding: utf-8 -*-
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import sys
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class Number:
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index: int
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value: int
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def __init__(self, index: int, value: int):
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self.index = index
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self.value = value
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def __eq__(self, other):
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if isinstance(other, Number):
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return self.index == other.index
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elif isinstance(other, int):
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return self.value == other
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return False
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def __hash__(self):
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return hash(self.index)
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def __str__(self):
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return str(self.value)
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def __repr__(self):
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return str(self)
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def decrypt(numbers: list[Number], key: int, rounds: int) -> int:
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numbers = numbers.copy()
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original = numbers.copy()
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numbers2index = {number: number.index for number in numbers}
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def swap(lhs: Number, rhs: Number):
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i1, i2 = numbers2index[lhs], numbers2index[rhs]
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numbers[i1], numbers[i2] = numbers[i2], numbers[i1]
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numbers2index[lhs], numbers2index[rhs] = i2, i1
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def move(index: int, value: int):
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assert value >= 0
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while value > 0:
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if index == len(numbers) - 1:
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swap(numbers[0], numbers[-1])
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index, value = 0, value - 1
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else:
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swap(numbers[index + 1], numbers[index])
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index, value = index + 1, value - 1
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for _ in range(rounds):
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for number in original:
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index = numbers2index[number]
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move(index, (number.value * key) % (len(numbers) - 1))
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index_of_0 = numbers.index(0)
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return sum(
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numbers[(index_of_0 + offset) % len(numbers)].value * key
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for offset in (1000, 2000, 3000)
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)
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numbers = [Number(i, int(x)) for i, x in enumerate(sys.stdin.readlines())]
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answer_1 = decrypt(numbers, 1, 1)
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print(f"answer 1 is {answer_1}")
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answer_2 = decrypt(numbers, 811589153, 10)
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print(f"answer 2 is {answer_2}")
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