@AoKSolution
object Day02ChunkGeneration : PuzDSL({
    fun Long.digits(): Int = log10(toDouble()).inc().toInt()
    val pow10 = LongArray(12) { 10.0.pow(it).toLong() }

    fun LongRange.sumInvalidIds(maxChunks: Int = endInclusive.digits()): Long {
        val seen = mutableSetOf<Long>()
        var sum = 0L

        fun visitRange(start: Long, end: Long) {
            val len = start.digits()
            for (chunks in 2..maxChunks) {
                if (len % chunks != 0) continue
                val chunkLen = len / chunks
                val chunkShift = pow10[chunkLen]
                val prefixShift = pow10[len - chunkLen]

                val startPrefix = start / prefixShift
                val endPrefix = end / prefixShift
                for (chunk in startPrefix..endPrefix) {
                    var invalid = chunk
                    repeat(chunks - 1) {
                        invalid *= chunkShift
                        invalid += chunk
                    }
                    if (invalid in start..end && seen.add(invalid)) sum += invalid
                }
            }
        }

        var start = start
        while (start < endInclusive) {
            val end = pow10[start.digits()]
            if (end <= endInclusive) visitRange(start, end - 1)
            else visitRange(start, endInclusive)
            start = end
        }
        return sum
    }

    val ranges = Parser {
        input.split(",", "-")
            .chunked(2) { (start, end) -> (start.toLong()..end.toLong()) }
    }

    part1(ranges) { ranges -> ranges.sumOf { it.sumInvalidIds(maxChunks = 2) } }
    part2(ranges) { ranges -> ranges.sumOf { it.sumInvalidIds() } }
})