class FocalLensCollection {
    private val lensBox = mutableMapOf<Int, MutableMap<String, Int>>()

    init {
        repeat(256) {
            lensBox[it] = mutableMapOf<String, Int>()
        }
    }

    fun sumUpHashes(commands: List<String>): Int {
        return commands.sumBy { hash(it) }
    }

    fun order(lenses: List<String>): Int {
        lenses.forEach { command ->
            val indexOfOperation = command.indexOfFirst { it == '-' || it == '=' }
            val label = command.substring(0 until indexOfOperation)
            val operation = command[indexOfOperation]
            val focus = command.substring((indexOfOperation+1) until command.length)
            val hash = hash(label)

            if (operation == '=') lensBox[hash]?.set(label, focus.toInt())
            else lensBox[hash]?.remove(label)
        }

        return lensBox.entries.map { box ->
            val boxValue = 1 + box.key
            box.value.values.mapIndexed { slotNumber, lensFocus ->
                boxValue * (slotNumber + 1) * lensFocus
            }.sum()
        }.sum()
    }

    fun hash(command: String): Int {
        return command.map { it.toInt() }.fold(0) { currentValue, characterValue ->
            ((currentValue + characterValue) * 17) % 256
        }
    }
}