57 lines
1.7 KiB
Nim
57 lines
1.7 KiB
Nim
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# Copyright 2021 Christian Ulrich
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# usage: ./part1 < input
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proc powerConsumption(): uint64 =
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var
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line = ""
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lineCount = 0'u64
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bitCounts: seq[uint64]
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while readLine(stdin, line):
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if line.len() > 0:
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if line.len() != bitCounts.len():
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if bitCounts.len() == 0:
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newSeq(bitCounts, line.len())
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else:
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raise newException(ValueError, "invalid line length")
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lineCount.inc()
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for index, digit in line.pairs():
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case digit
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of '0': discard
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of '1': bitCounts[index].inc()
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else: raise newException(ValueError, "invalid digit")
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var
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gamma = 0'u64
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epsilon = 0'u64
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for index, bitCount in bitCounts.pairs():
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let bitPosition = bitCounts.len() - 1 - index
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let mask = 1'u64 shl uint64(bitPosition)
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if bitCount > lineCount div 2:
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gamma = gamma or mask
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else:
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epsilon = epsilon or mask
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result = gamma * epsilon
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proc main(): int =
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try:
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echo powerConsumption()
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except Exception as error:
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echo error.msg
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result = -1
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when isMainModule:
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quit(main())
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