commit cb0c66368b1bff14f24740e5d0c03823bae06086 · aylac.top/advent_of_code

+58 -22
2025/4/gleam/src/main.gleam
···

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       import gleam/string

     

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       import simplifile as file

     

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       -
       fn solve(input, size) {

     

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         let get_place = fn(x, y) {

     

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           case

     

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             case x, y {

     

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               _, -1 | -1, _ -> <<>>

     

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               s, _ | _, s if s == size -> <<>>

     

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       fn get_place(x, y, map, size) {

     

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         case

     

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           case x, y {

     

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             _, -1 | -1, _ -> <<>>

     

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             s, _ | _, s if s == size -> <<>>

     

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               _, _ -> bit_array.slice(input, y * size + x, 1) |> result.unwrap(<<>>)

     

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             }

     

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           {

     

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             <<"@">> -> 1

     

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             _ -> 0

     

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             _, _ -> bit_array.slice(map, y * size + x, 1) |> result.unwrap(<<>>)

     

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           }

     

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         {

     

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           <<"@">> -> 1

     

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           _ -> 0

     

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         }

     

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       }

     

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         list.range(0, bit_array.byte_size(input) - 1)

     

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       fn part_1(map, size) {

     

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         list.range(0, bit_array.byte_size(map) - 1)

     

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         |> list.fold(0, fn(acc, pos) {

     

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           let x = pos % size

     

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           let y = pos / size

     

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           let roll = get_place(x, y)

     

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           let roll = get_place(x, y, map, size)

     

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           let neighbours =

     

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             get_place(x - 1, y - 1)

     

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             + get_place(x, y - 1)

     

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             + get_place(x + 1, y - 1)

     

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             + get_place(x - 1, y)

     

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             + get_place(x + 1, y)

     

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             + get_place(x - 1, y + 1)

     

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             + get_place(x, y + 1)

     

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             + get_place(x + 1, y + 1)

     

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             get_place(x - 1, y - 1, map, size)

     

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             + get_place(x, y - 1, map, size)

     

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             + get_place(x + 1, y - 1, map, size)

     

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             + get_place(x - 1, y, map, size)

     

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             + get_place(x + 1, y, map, size)

     

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             + get_place(x - 1, y + 1, map, size)

     

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             + get_place(x, y + 1, map, size)

     

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             + get_place(x + 1, y + 1, map, size)

     

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           case roll, neighbours < 4 {

     

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             1, True -> acc + 1

     
···

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         })

     

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       }

     

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       fn part_2(map, size, rolls) {

     

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         let #(rolls, new_map) =

     

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           list.range(0, bit_array.byte_size(map) - 1)

     

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           |> list.fold(#(rolls, <<>>), fn(acc, pos) {

     

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             let #(total, new_map) = acc

     

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             let x = pos % size

     

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             let y = pos / size

     

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             let roll = get_place(x, y, map, size)

     

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             let neighbours =

     

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               get_place(x - 1, y - 1, map, size)

     

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               + get_place(x, y - 1, map, size)

     

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               + get_place(x + 1, y - 1, map, size)

     

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               + get_place(x - 1, y, map, size)

     

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               + get_place(x + 1, y, map, size)

     

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               + get_place(x - 1, y + 1, map, size)

     

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               + get_place(x, y + 1, map, size)

     

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               + get_place(x + 1, y + 1, map, size)

     

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             case roll, neighbours < 4 {

     

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               1, True -> #(total + 1, bit_array.append(new_map, <<".">>))

     

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               0, _ -> #(total, bit_array.append(new_map, <<".">>))

     

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               1, _ | _, _ -> #(total, bit_array.append(new_map, <<"@">>))

     

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             }

     

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           })

     

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         case map == new_map {

     

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           True -> rolls

     

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           False -> part_2(new_map, size, rolls)

     

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         }

     

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       }

     

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       pub fn main() {

     

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         let assert Ok(input) = file.read(from: "../input.txt")

     

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           as "Input file not found"

     
···

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         let input = input |> list.fold(<<>>, fn(acc, l) { bit_array.append(acc, l) })

     

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         // @ and .

     

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         solve(input, size)

     

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         part_1(input, size)

     

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         |> int.to_string

     

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         |> io.println

     

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         part_2(input, size, 0)

     

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         |> int.to_string

     

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         |> io.println

     

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       }