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class Bingo(private val revealQueue: ArrayDeque<Int>, private val boards: List<Board>) {
companion object {
fun fromString(input: String): Bingo {
val sections = input.trim().split("(\\r?\\n){2}".toRegex())
val revealQueueString = sections.first()
val revealQueue = ArrayDeque(revealQueueString.split(",").map(String::toInt))
val boards = sections.drop(1).map { Board.fromMatrixString(it) }
return Bingo(revealQueue, boards)
}
}
fun getResults() = sequence {
while (revealQueue.isNotEmpty() && boards.any { !it.didWin }) {
val number = revealQueue.removeFirst()
for (board in boards.filter { !it.didWin }) {
board.reveal(number)
if (board.didWin) {
yield(board.sumOfUnmarked * number)
}
}
}
}
class Board(private var rows: List<List<Square>>) {
companion object {
fun fromMatrixString(matrixString: String): Board = Board(
matrixString.trim().split("\\r?\\n".toRegex()).map { rowString ->
rowString.trim().split("\\s+".toRegex()).map { squareString ->
Square.Unmarked(squareString.toInt())
}
}
)
private const val SIZE = 5
private val ROWS = (0 until SIZE).map { row ->
(0 until SIZE).map { square ->
Pair(row, square)
}
}
private val COLUMNS = (0 until SIZE).map { column ->
(0 until SIZE).map { square ->
Pair(square, column)
}
}
private val WINNING_CONFIGURATIONS = ROWS + COLUMNS
}
fun reveal(number: Int) {
rows = rows.map { row ->
row.map { square ->
if (square is Square.Unmarked && square.number == number) Square.Marked else square
}
}
}
val didWin: Boolean
get() = WINNING_CONFIGURATIONS.any { configuration ->
configuration.all { (row, column) -> rows[row][column] is Square.Marked }
}
val sumOfUnmarked: Int
get() = rows.fold(0) { racc, row ->
racc + row.fold(0) { sacc, square ->
sacc + if (square is Square.Unmarked) square.number else 0
}
}
sealed class Square {
object Marked : Square()
class Unmarked(val number: Int) : Square()
}
}
}
fun main() {
fun part1(input: String): Int = Bingo.fromString(input).getResults().first()
fun part2(input: String): Int = Bingo.fromString(input).getResults().last()
val testInput = readInputAsString("Day04_test")
check(part1(testInput) == 4512)
check(part2(testInput) == 1924)
val input = readInputAsString("Day04")
println(part1(input))
println(part2(input))
}
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