Finish 2024 day 19 both parts

2024/kotlin/src/main/kotlin/Main.kt

@@ -18,6 +18,7 @@ import com.tymscar.day15.solve as day15
 import com.tymscar.day16.solve as day16
 import com.tymscar.day17.solve as day17
 import com.tymscar.day18.solve as day18
+import com.tymscar.day19.solve as day19
 
 fun main() {
     day01()
@@ -38,4 +39,5 @@ fun main() {
     day16()
     day17()
     day18()
+    day19()
 }

2024/kotlin/src/main/kotlin/com/tymscar/day19/part1/part1.kt

@@ -1,5 +1,20 @@
 package com.tymscar.day19.part1
 
+private fun getValidDesigns(designs: List<String>, towels: List<String>): List<String> = designs
+    .filter {
+        Regex("""^(${towels.joinToString("|")})+$""")
+            .matches(it)
+    }
+
 fun solve(input: String): String {
-    return input
+    val towels = input
+        .split("\n\n")[0]
+            .split(", ")
+    val designs = input
+        .split("\n\n")[1]
+            .lines()
+
+    return getValidDesigns(designs, towels)
+        .count()
+        .toString()
 }

2024/kotlin/src/main/kotlin/com/tymscar/day19/part2/part2.kt

@@ -1,5 +1,40 @@
 package com.tymscar.day19.part2
 
+private fun isValidDesign(design: String, towels: List<String>): Boolean =
+    Regex("""^(${towels.joinToString("|")})+$""")
+        .matches(design)
+
+private fun waysToMake(
+    design: String,
+    towels: List<String>,
+    memo: HashMap<String, Long>
+): Long {
+    if (memo.contains(design)) return memo[design]!!
+    if (!isValidDesign(design, towels)) return 0
+
+    val result = towels.sumOf {
+        when {
+            design == it -> 1
+            design.startsWith(it) -> waysToMake(design.removePrefix(it), towels, memo)
+            else -> 0
+        }
+    }
+
+    memo[design] = result
+    return result
+}
+
 fun solve(input: String): String {
-    return input
+    val towels = input
+        .split("\n\n")[0]
+        .split(", ")
+    val designs = input
+        .split("\n\n")[1]
+        .lines()
+
+    val memo = HashMap<String, Long>()
+
+    return designs
+        .sumOf { waysToMake(it, towels, memo) }
+        .toString()
 }