Solved Day02 and Day03 of 2022.

src/aoc2022/Day02.kt

@@ -0,0 +1,30 @@
+fun main() {
+    // A = 0   X = 0   Win: X0 - C2, Z2 - B1, Y1 - A0
+    // B = 1   Y = 1   Win: (r+2) % 3) == c; Lose: ((r+1) % 3) == c
+    // C = 2   Z = 2   Points = (r + 1) + ((3-c) - (r+1) % 3) * 3
+    fun part1(input: List<String>): Int {
+        return input.sumOf {
+            val c = it[0] - 'A'
+            val r = it[2] - 'X'
+            (r + 1) + ((r - c + 4) % 3) * 3
+        }
+    }
+
+    fun part2(input: List<String>): Int {
+        return input.sumOf {
+            val c = it[0] - 'A'
+            val l = it[2] - 'X'
+            val r = (l - c * 2 + 8) % 3
+            (r + 1) + ((r - c + 4) % 3) * 3
+        }
+    }
+
+    // test if implementation meets criteria from the description, like:
+    val testInput = readInput("aoc2022/Day02_test")
+    check(part1(testInput) == 15)
+    check(part2(testInput) == 12)
+
+    val input = readInput("aoc2022/Day02")
+    part1(input).println()
+    part2(input).println()
+}

src/aoc2022/Day03.kt

@@ -0,0 +1,32 @@
+fun main() {
+
+    fun toPrio(input: Char) = if (input in 'A'..'Z') input - 'A' + 27 else input - 'a' + 1
+
+    fun part1(input: List<String>): Int =
+        input.sumOf {
+            val seen = IntArray(2 * 26 + 1)
+            it.subSequence(0, it.length / 2).forEach { seen[toPrio(it)] = 1 }
+            it.subSequence(it.length / 2, it.length).forEach { seen[toPrio(it)] = seen[toPrio(it)] or 2 }
+            seen.withIndex().find { it.value == 3 }!!.index
+        }
+
+    fun part2(input: List<String>): Int =
+        input.chunked(3)
+            .sumOf {
+                val seen = IntArray(2 * 26 + 1)
+                it[0].forEach { seen[toPrio(it)] = 1 }
+                it[1].forEach { seen[toPrio(it)] = seen[toPrio(it)] or 2 }
+                it[2].forEach { seen[toPrio(it)] = seen[toPrio(it)] or 4 }
+                seen.withIndex().find { it.value == 7 }!!.index
+            }
+
+    // test if implementation meets criteria from the description, like:
+    val testInput = readInput("aoc2022/Day03_test")
+    part1(testInput).println()
+    check(part1(testInput) == 157)
+    check(part2(testInput) == 70)
+
+    val input = readInput("aoc2022/Day03")
+    part1(input).println()
+    part2(input).println()
+}