65 lines
1.5 KiB
Scala
65 lines
1.5 KiB
Scala
|
package aoc.day3
|
||
|
|
|
||
|
|
import aoc._
|
||
|
|
import scala.collection.mutable.ArrayBuffer
|
||
|
|
import scala.math.BigInt
|
||
|
|
|
||
|
|
val board = lines.toArray
|
||
|
|
|
||
|
|
val numbers = board.toIterator.zipWithIndex.flatMap { (line, row) =>
|
||
|
|
var col = 0
|
||
|
|
var buf: ArrayBuffer[(Int, Int, String)] = ArrayBuffer.empty
|
||
|
|
while col < line.length do
|
||
|
|
if line(col).isDigit then
|
||
|
|
val numStr = line.slice(col, line.length()).takeWhile(_.isDigit)
|
||
|
|
buf += ((row, col, numStr))
|
||
|
|
col += numStr.length()
|
||
|
|
else col += 1
|
||
|
|
buf
|
||
|
|
}.toSeq
|
||
|
|
|
||
|
|
def adjacent(x: Int, y: Int) =
|
||
|
|
Seq(-1, 0, 1).flatMap { dx => Seq(-1, 0, 1).map(dy => (x + dx, y + dy)) }
|
||
|
|
|
||
|
|
// Part 1
|
||
|
|
|
||
|
|
def adjacentCells(x: Int, y: Int) =
|
||
|
|
adjacent(x, y)
|
||
|
|
.filter((x, y) =>
|
||
|
|
x >= 0 && x < board.length && y >= 0 && y < board(x).length
|
||
|
|
)
|
||
|
|
.map((x, y) => board(x)(y))
|
||
|
|
|
||
|
|
def part1 =
|
||
|
|
val numbersWithSyms = numbers
|
||
|
|
.filter((x, y, num) =>
|
||
|
|
(y until y + num.length()).exists(y =>
|
||
|
|
adjacentCells(x, y).exists(c => !c.isDigit && c != '.')
|
||
|
|
)
|
||
|
|
)
|
||
|
|
.map(v => BigInt(v._3))
|
||
|
|
.sum
|
||
|
|
println(numbersWithSyms)
|
||
|
|
|
||
|
|
// Part 2
|
||
|
|
|
||
|
|
def adjacentNums(x: Int, y: Int) =
|
||
|
|
numbers.filter((nx, ny, n) =>
|
||
|
|
(x - nx).abs <= 1 && ny <= y + 1 && ny + n.length() >= y
|
||
|
|
)
|
||
|
|
|
||
|
|
def part2 =
|
||
|
|
val gears = board.toIterator.zipWithIndex
|
||
|
|
.flatMap { (line, row) =>
|
||
|
|
line.zipWithIndex.filter(_._1 == '*').map(v => (row, v._2))
|
||
|
|
}
|
||
|
|
.map(adjacentNums)
|
||
|
|
.filter(_.length == 2)
|
||
|
|
.map(s => s.map(v => BigInt(v._3)).product)
|
||
|
|
.sum
|
||
|
|
println(gears)
|
||
|
|
|
||
|
|
@main def Day3(part: Int) = part match
|
||
|
|
case 1 => part1
|
||
|
|
case 2 => part2
|