diff --git a/2021/src/main/kotlin/Day04.kt b/2021/src/main/kotlin/Day04.kt
index 80b247f..14df4b9 100644
--- a/2021/src/main/kotlin/Day04.kt
+++ b/2021/src/main/kotlin/Day04.kt
@@ -5,46 +5,27 @@ import be.vandewalleh.aoc.utils.input.Day
 
 @Day
 class Day04 : BaseDay() {
-    private val parts by lazy { input.text.split("\n\n") }
-    private val numbers by lazy { parts[0].split(',').map { it.toInt() } }
+    private val numbers by lazy { input.lines.value[0].split(',').map { it.toInt() } }
     private val boards by lazy {
-        parts.drop(1)
+        input.text.split("\n\n")
+            .drop(1)
             .map { it.lines().map { it.trim().split("\\s+".toRegex()).map { it.toInt() } } }
     }
 
-    override fun part1() = boards
-        .map { playBoard(it, numbers) }
-        .minByOrNull { it.first }!!
-        .second
+    private val results by lazy { boards.map { playBoard(it) } }
 
-    override fun part2() = boards
-        .map { playBoard(it, numbers) }
-        .maxByOrNull { it.first }!!
-        .second
+    override fun part1() = results.minByOrNull { it.first }!!.second
+    override fun part2() = results.maxByOrNull { it.first }!!.second
 
-    private fun playBoard(board: List<List<Int>>, numbers: List<Int>): Pair<Int, Int> {
+    private fun playBoard(board: List<List<Int>>): Pair<Int, Int> {
         for (round in numbers.indices) {
             val usedNumbers = numbers.take(round)
-            var winning = false
-            for (line in board) {
+            for (line in board + board[0].indices.map { col -> board.map { it[col] } }) {
                 if (usedNumbers.containsAll(line)) {
-                    winning = true
-                    break
+                    val unmarkedNumbers = board.flatten().toMutableSet().also { it.removeAll(usedNumbers) }
+                    return round to unmarkedNumbers.sum() * usedNumbers.last()
                 }
             }
-            if (!winning) {
-                for (i in board[0].indices) {
-                    val column = board.map { it[i] }
-                    if (usedNumbers.containsAll(column)) {
-                        winning = true
-                        break
-                    }
-                }
-            }
-            if (winning) {
-                val unmarkedNumbers = board.flatten().toMutableSet().also { it.removeAll(usedNumbers) }
-                return round to unmarkedNumbers.sum() * usedNumbers.last()
-            }
         }
         error("No wins")
     }