Day 22 part 1

2024/src/main/kotlin/day22.kt

@@ -0,0 +1,17 @@
+fun main() {
+    val part1 =  readInput("day22.txt")
+        .map { it.toLong() }
+        .map { randomSequence(it).elementAt(2000) }
+        .sum()
+
+    println("Part 1: $part1")
+}
+
+fun prune(x: Long) = x % 16777216
+fun mix(a: Long, b: Long) = a xor b
+
+fun randomSequence(start: Long) = generateSequence(start) { current ->
+    val a = prune(mix(current, current * 64))
+    val b = prune(mix(a, a / 32))
+    prune(mix(b, b * 2048))
+}