use shifting start index instead of sublists

Author: peckb1

src/main/kotlin/me/peckb/aoc/_2025/calendar/day03/Day03.kt

@@ -17,10 +17,9 @@ class Day03 @Inject constructor(
   private fun maxJoltage(
     batteryArray: List<Long>,
     startIndex: Int = 0,
-    endIndex: Int = batteryArray.size - 1,
     numToEnable: Int,
   ) : Long {
-    val subListIndices = startIndex .. (endIndex - (numToEnable - 1))
+    val subListIndices = startIndex .. ((batteryArray.size - 1) - (numToEnable - 1))
 
     val indexOfLargest = subListIndices.maxBy { i -> batteryArray[i] }
     val largestStartValue = batteryArray[indexOfLargest]
@@ -30,7 +29,7 @@ class Day03 @Inject constructor(
 
     // if we have more batteries to flip - find the indices for those batteries and send down the new arrays
     val possibleStartIndices = subListIndices.filter { i -> batteryArray[i] == largestStartValue }
-    val maxSubJoltage = possibleStartIndices.maxOf { i -> maxJoltage(batteryArray.drop(i + 1), numToEnable = numToEnable - 1) }
+    val maxSubJoltage = possibleStartIndices.maxOf { i -> maxJoltage(batteryArray, startIndex = i + 1, numToEnable = numToEnable - 1) }
 
     // then add it to our value and return!
     return "$largestStartValue$maxSubJoltage".toLong()