Date.kt

interface Day {

    fun part1(input: String) = part1(listOf(input))
    fun part2(input: String) = part2(listOf(input))

    fun part1(input: List<String>): String
    fun part2(input: List<String>): String

    fun solve(inputPart1: String, inputPart2: String): List<String, String>  {
        return List<String, String>(
          part1(inputPart1),
          part2(inputPart2)
        )
    }
}