80 lines
1.6 KiB
Python
80 lines
1.6 KiB
Python
report = []
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with open("input.txt") as f:
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lines = f.read().split('\n')
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for line in lines:
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report.append(line)
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gamma = ''
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for i in range(len(report[0])):
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ones_count = 0
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for number in report:
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if number[i] == '1':
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ones_count += 1
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half = len(report) / 2
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if ones_count > half:
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gamma += '1'
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else:
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gamma += '0'
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power = 2 ** len(gamma) - 1
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gamma = int(gamma, 2)
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epsilon = power - gamma
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part1 = gamma * epsilon
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print(part1)
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o2_candidates = set()
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co2_candidates = set()
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for number in report:
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o2_candidates.add(number)
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co2_candidates.add(number)
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for i in range(len(report[0])):
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if len(o2_candidates) == 1:
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break
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# first pass: count the bits in each position
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ones_count = 0
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zeros_count = 0
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for number in o2_candidates:
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if number[i] == '0':
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zeros_count += 1
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else:
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ones_count += 1
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# Keep 1, unless 0 is more common.
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if zeros_count > ones_count:
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keep = '0'
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else:
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keep = '1'
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# second pass: filter out the candidates
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for number in o2_candidates.copy():
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if number[i] != keep:
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o2_candidates.remove(number)
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for i in range(len(report[0])):
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if len(co2_candidates) == 1:
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break
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# first pass: count the bits in each position
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ones_count = 0
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zeros_count = 0
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for number in co2_candidates:
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if number[i] == '0':
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zeros_count += 1
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else:
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ones_count += 1
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# Keep 0, unless 1 is less common.
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if ones_count < zeros_count:
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keep = '1'
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else:
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keep = '0'
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# second pass: filter out the candidates
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for number in co2_candidates.copy():
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if number[i] != keep:
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co2_candidates.remove(number)
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o2 = int(o2_candidates.pop(), 2)
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co2 = int(co2_candidates.pop(), 2)
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part2 = o2 * co2
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print(part2)
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