94 lines
2.7 KiB
Forth
94 lines
2.7 KiB
Forth
namespace AdventOfCode2023
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[<RequireQualifiedAccess>]
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module Day11 =
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type Data =
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{
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RowsWithoutGalaxies : ResizeArray<int>
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ColsWithoutGalaxies : ResizeArray<int>
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/// row * col
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Galaxies : ResizeArray<int * int>
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}
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let parse (s : string) : Data =
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let galaxies = ResizeArray ()
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let rowsWithoutGalaxies = ResizeArray ()
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let mutable hasAnyGalaxy = false
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let mutable currRowIndex = 0
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let mutable currColIndex = 0
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for c in s do
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if c = '\n' then
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if not hasAnyGalaxy then
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rowsWithoutGalaxies.Add currRowIndex
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currRowIndex <- currRowIndex + 1
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currColIndex <- 0
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hasAnyGalaxy <- false
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elif c = '#' then
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hasAnyGalaxy <- true
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galaxies.Add (currRowIndex, currColIndex)
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currColIndex <- currColIndex + 1
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else
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currColIndex <- currColIndex + 1
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galaxies.Sort (fun (_, c1) (_, c2) -> compare c1 c2)
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let colsWithoutGalaxies =
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let result = ResizeArray ()
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let mutable prevCol = 0
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for _, c in galaxies do
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if c > prevCol then
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for j = prevCol + 1 to c - 1 do
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result.Add j
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prevCol <- c
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result
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{
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RowsWithoutGalaxies = rowsWithoutGalaxies
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ColsWithoutGalaxies = colsWithoutGalaxies
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Galaxies = galaxies
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}
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let solve (data : Data) (expansion : uint64) =
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let mutable answer = 0uL
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for galaxy1 = 0 to data.Galaxies.Count - 1 do
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let row1, col1 = data.Galaxies.[galaxy1]
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for galaxy2 = galaxy1 + 1 to data.Galaxies.Count - 1 do
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let row2, col2 = data.Galaxies.[galaxy2]
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let baseDistance = uint64 (abs (row1 - row2) + abs (col1 - col2))
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let extraDistance =
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let mutable extraDistance = 0uL
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for i = 1 + min row1 row2 to max row1 row2 - 1 do
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if data.RowsWithoutGalaxies.Contains i then
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extraDistance <- extraDistance + expansion - 1uL
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for i = 1 + min col1 col2 to max col1 col2 - 1 do
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if data.ColsWithoutGalaxies.Contains i then
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extraDistance <- extraDistance + expansion - 1uL
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extraDistance
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answer <- answer + extraDistance + baseDistance
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answer
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let part1 (s : string) =
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let data = parse s
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solve data 2uL
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let part2 (s : string) =
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let data = parse s
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solve data 1_000_000uL
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