Add Input.findAll

2021/src/main/kotlin/Day14.kt

@@ -8,16 +8,13 @@ class Day14 : BaseDay() {
 
     private fun run(step: Int): Long {
         val template = input.lines.value.first()
-        // {CH=(CB, BH), NN=(NC, CN), ...}
-        val pairs = input.lines.value.drop(2)
-            .associate { it.split(" -> ").let { (a, b) -> a to (a[0] + b to b + a[1]) } }
-
+        val pairs = input.findAll("(\\S+) -> (\\S)").associate { it[0] to it[1] }
         val polymer = Counter(template.windowed(2)) // {NN=1, NC=1, CB=1}
         val counts = Counter(template.toCharArray().toList()) // {N=2, C=1, ...}
 
         repeat(step) {
             polymer.forEach { (pair, value) ->
-                val (left, right) = pairs[pair]!!
+                val (left, right) = pairs[pair]!!.let { m -> pair[0] + m to m + pair[1] }
                 polymer[pair] -= value
                 polymer[left] += value
                 polymer[right] += value