Restored deleted code from previous commit and used it to solve Part 1 much faster.

src/aoc2025/Day10.kt

@@ -41,23 +41,17 @@ fun main() {
         val machines = parse(input)
         var sumButts = 0
         for (m in machines) {
-            val pq = LinkedList<Pair<Int, Int>>()
+            // look at which different possible sets of toggles need to be pressed to result in the target number
-            val killArray = BooleanArray(1 shl m.size)
+            // pressing an even time will cancel out the effect, so only look what happens if you press once
-            pq.add(0 to 0)
+            var minPresses = Int.MAX_VALUE
-            out@ while (pq.isNotEmpty()) {
+            for (tm in 1 until (1 shl m.toggles.size)) {
-                val (v, bi) = pq.poll()
+                val odds = m.toggles.filterIndexed { i, v -> (1 shl i) and tm != 0 }
-                for (t in m.toggles) {
+                val result = odds.fold(0) { acc, iv -> acc xor iv }
-                    val nv = v xor t
+                if (result == m.target) {
-                    if (nv == m.target) {
+                    minPresses = minPresses.coerceAtMost(odds.size)
-                        sumButts += bi + 1
-                        break@out
-                    }
-                    if (!killArray[nv]) {
-                        killArray[v] = true
-                        pq.add(nv to bi + 1)
-                    }
                 }
             }
+            sumButts += minPresses
         }
         return sumButts
     }
@@ -103,7 +97,8 @@ fun main() {
         for (m in machines) {
             // generate toggles and calculate the global maximum of toggle presses for this toggle
             val toggles = m.toggles.mapIndexed { i, t ->
-                Toggle(i,
+                Toggle(
+                    i,
                     t,
                     max = IntRange(0, m.size).filter { b -> t and (1 shl b) != 0 }.minOf { m.joltage[it] })
             }
@@ -128,7 +123,6 @@ fun main() {
                 v.min = minT
             }
 
-            // iterate over the possible odd sets
             var minPushes = Int.MAX_VALUE
             val jolts = m.joltage.copyOf()
             val pressCount = IntArray(m.toggles.size)