44 lines
1.3 KiB
Nim
44 lines
1.3 KiB
Nim
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import lib/[loader, util]
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proc isValid(numbers: seq[int], idx: int, size = 25): bool =
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# find two previous numbers that sum to the given number
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let slice = (idx - size) .. (idx - 1)
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for a in slice:
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for b in slice:
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if a == b:
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continue
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elif numbers[a] + numbers[b] == numbers[idx]:
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return true
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return false
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proc findRangeWithSum(numbers: seq[int]; target: int): (int, int) =
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for start in 0 .. (numbers.high - 1):
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for stop in (start + 1) .. numbers.high:
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var total = 0
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for i in start .. stop:
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total += numbers[i]
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if total == target:
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return (start, stop)
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raise newException(ValueError, "Could not find a range of numbers adding to " & $target)
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proc partOne(numbers: seq[int]): int =
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for idx in 25 .. numbers.high:
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if not isValid(numbers, idx):
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return numbers[idx]
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raise newException(ValueError, "Could not find an invalid value")
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proc partTwo(numbers: seq[int]): int =
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let target = partOne(numbers)
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let (start, stop) = numbers.findRangeWithSum(target)
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return min(numbers[start..stop]) + max(numbers[start..stop])
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when isMainModule:
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let data = loadInts(9)
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echo "One: ", partOne(data)
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echo "Two: ", partTwo(data)
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