draft puzzle state with hexadecimals

Main.kt

import java.math.BigInteger
import kotlin.math.max
import kotlin.math.min

fun Long.toHexString(): String = BigInteger(this.toString()).toString(16)

class Hexrray(var n: Long) {

  operator fun get(i: Int) =
    (n shr (48 - ((min(48, i + 1)) * 4))) and 0xf

  operator fun set(i: Int, value: Long) {
    val idx = 48 - (min(48, i + 1) * 4)
    n = n and (0xFL shl idx).inv()
    n = n or (value shl idx)
  }

  fun swap(idxA: Int, idxB: Int) {
    val i = min(idxA, idxB)
    val j = max(idxA, idxB)
    val a = this[i]
    val b = this[j]
    this[i] = b
    this[j] = a
  }
}

class Dino(var state: Long = 0x123456789abc) {

  private val hexrray = Hexrray(state)

  fun move(m: Int) {
    // TODO
  }

  override fun toString() = hexrray.n.toHexString()
}

fun main() {
  val d = Dino()
}