AoC/2023/Day04Pt1.kt

fun main() {

    val reg = Regex("[\\d]+")
    fun getNumberOfWins(input: String): Int {
        val (winning, held) = input.split(": ")[1].split(" | ")

        val winningSet = reg.findAll(winning).map { it.groupValues[0] }.toList();
        val heldSet = reg.findAll(held).map { it.groupValues[0] }.toList();

        return winningSet.intersect(heldSet).size
    }

    // Using val because I think the alternative makes solution harder to read.
    val zeroAsDouble = 0.toDouble()

    fun part1(input: List<String>): Int {
        val output = input.map { getNumberOfWins(it) } // get match count for each card
            .map { n ->
                if (n > 0) 2.toDouble().pow(n - 1) // score the card if any matches
                else zeroAsDouble // 0 if none
            }
            .sum() // sum

        return output.toInt();
    }

    val input = Path("src/Day04.txt").readLines()
    part1(input).println()
}