40 lines
938 B
Nim
40 lines
938 B
Nim
import
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std/math,
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std/options,
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std/sequtils,
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std/strformat,
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std/strutils
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import
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../../adventofcode
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type
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Grid = seq[seq[int]]
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proc at(g: Grid; x, y: int): Option[int] =
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try: result = some g[y][x]
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except IndexDefect: discard
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let input = adventofcode.getInput(2021, 9)
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let grid = Grid input.splitLines().mapIt(toSeq(it).mapIt(($it).parseInt()))
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var lowPoints = newSeq[int]()
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for y in 0 .. grid.high():
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for x in 0 .. grid[y].high():
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let p = grid.at(x, y).get()
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let adjA = grid.at(x - 1, y)
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if adjA.isSome() and p >= adjA.get(): continue
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let adjB = grid.at(x, y - 1)
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if adjB.isSome() and p >= adjB.get(): continue
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let adjC = grid.at(x + 1, y)
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if adjC.isSome() and p >= adjC.get(): continue
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let adjD = grid.at(x, y + 1)
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if adjD.isSome() and p >= adjD.get(): continue
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lowPoints.add p
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var riskLevels = lowPoints.mapIt(it + 1)
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echo fmt"Answer: {math.sum riskLevels}" |