92 lines
2.7 KiB
Nim
92 lines
2.7 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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import sequtils
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import strutils
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type
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Point = tuple[x: uint16, y: uint16]
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Line = tuple[start: Point, `end`: Point]
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Orientation = enum
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Horizontal, Vertical, Diagonal
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Area = array[1000, array[1000, uint8]]
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proc orientation(line: Line): Orientation =
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if line.start.y == line.end.y:
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result = Horizontal
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elif line.start.x == line.end.x:
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result = Vertical
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else:
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result = Diagonal
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proc add(area: var Area, line: Line) =
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case line.orientation()
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of Horizontal:
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for x in line.start.x .. line.end.x:
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area[x][line.start.y].inc()
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of Vertical:
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for y in line.start.y .. line.end.y:
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area[line.start.x][y].inc()
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of Diagonal:
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assert(false, "not implemented")
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proc initLine(start, `end`: Point): Line =
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result = (start: start, `end`: `end`)
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let orientation = result.orientation()
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if orientation == Horizontal and result.start.x > result.end.x or
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orientation == Vertical and result.start.y > result.end.y or
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orientation == Diagonal and result.start.x > result.end.x:
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result = (start: result.end, `end`: result.start)
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proc parsePoint(input: string): Point =
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let coords = input.split(',', 1)
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if coords.len() != 2:
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raise newException(ValueError, "invalid point")
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result = (x: uint16(parseUint(coords[0])), y: uint16(parseUint(coords[1])))
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proc parseLines(): seq[Line] =
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var line = ""
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while readLine(stdin, line):
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if line.len() > 0:
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let tokens = line.split(' ', 2)
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if tokens.len() != 3 or tokens[1] != "->":
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raise newException(ValueError, "invalid line")
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result.add(initLine(parsePoint(tokens[0]), parsePoint(tokens[2])))
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proc countOverlaps(): int =
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let lines = parseLines()
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var area: Area
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for line in lines.filterIt(it.orientation() in [Horizontal, Vertical]):
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area.add(line)
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for x in 0 .. high(area):
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for y in 0 .. high(area[0]):
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if area[x][y] > 1:
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result.inc()
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proc main(): int =
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try:
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echo countOverlaps()
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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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