43 lines
1.2 KiB
Python
43 lines
1.2 KiB
Python
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#!/usr/bin/env python3
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import fileinput
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from copy import deepcopy
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numbers = [[int(i) for i in line.strip()] for line in fileinput.input()]
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bit_count = len(numbers[0])
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occurrences = [0] * bit_count
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for number in numbers:
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for i, bit in enumerate(number):
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occurrences[i] += bit
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gamma, epsilon = 0, 0
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for i, freq in enumerate(occurrences):
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shifted = 1 << (len(occurrences) - 1) >> i
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if freq > len(numbers) // 2:
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gamma |= shifted
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else:
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epsilon |= shifted
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print("part 1:", gamma * epsilon)
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most_common = deepcopy(numbers)
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least_common = deepcopy(numbers)
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for i in range(bit_count):
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ones = sum(number[i] for number in most_common)
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lc = int(ones * 2 >= len(most_common))
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most_common = [number for number in most_common if number[i] == lc]
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if len(most_common) == 1:
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break
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for i in range(bit_count):
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zeros = sum(not number[i] for number in least_common)
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lc = int(zeros * 2 > len(least_common))
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least_common = [number for number in least_common if number[i] == lc]
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if len(least_common) == 1:
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break
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mc = int("".join(str(x) for x in most_common[0]), 2)
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lc = int("".join(str(x) for x in least_common[0]), 2)
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print("part 2:", mc * lc)
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