Replace REM with MOD.

Author: lakiboy

src/main/kotlin/io/dmitrijs/aoc2022/Day20.kt

@@ -1,8 +1,5 @@
 package io.dmitrijs.aoc2022
 
-import kotlin.math.absoluteValue
-import kotlin.math.sign
-
 class Day20(private val input: List<Long>) {
  fun puzzle1() = decipher()
 
@@ -25,17 +22,9 @@ class Day20(private val input: List<Long>) {
  private fun List<Number>.zeroIndex() = indexOfFirst { it.value == 0L }
 
  private fun MutableList<Number>.mix(order: Int) {
- val index = indexOfFirst { it.order == order }
- val value = this[index].value
-
- val rawIndex = (index + value.sign * (value.absoluteValue % lastIndex)).toInt()
- val newIndex = when {
- rawIndex <= 0 -> size - (rawIndex.absoluteValue + 1)
- rawIndex >= size -> rawIndex % size + 1
- else -> rawIndex
- }
-
- add(newIndex, removeAt(index))
+ val oldIndex = indexOfFirst { it.order == order }
+ val newIndex = (oldIndex + this[oldIndex].value).mod(size - 1)
+ add(newIndex, removeAt(oldIndex))
  }
 
  private fun <T> List<T>.nth(num: Int) = this[num % size]