Day1-3

input/day3/input

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src/main/kotlin/Day1.kt

@@ -2,11 +2,18 @@ import java.io.File
 
 fun main() {
     println("Hello day1!")
-    solve()
+    solveDay1()
 }
 
-fun solve() {
+fun solveDay1() {
-    val readLines = File("input/day1/input").readLines()
+    val text = File("input/day1/input").readText()
-
+    val elvCalories = text.split("\n\n").map { it.trim() }
-    println("${readLines.size}")
+    val summedCalories = elvCalories
+        .map {
+            it.split("\n")
+                .sumOf { l -> l.toLong() }
+        }
+
+    println(summedCalories.max())
+    println(summedCalories.sortedDescending().take(3).sum())
 }

src/main/kotlin/Day2.kt

@@ -0,0 +1,50 @@
+import java.io.File
+
+fun main() {
+    println("Hello day2!")
+    solveDay2()
+}
+
+fun solveDay2() {
+    val lines = File("input/day2/input").readLines()
+    val scores1 = lines.map { l ->
+        val s = l.split(" ")
+        scorePart1(s[0], s[1])
+    }
+    val scores2 = lines.map { l ->
+        val s = l.split(" ")
+        scorePart2(s[0], s[1])
+    }
+    println(scores1.sum())
+    println(scores2.sum())
+}
+
+fun scorePart1(other: String, me: String): Long {
+    return when {
+        other == "A" && me == "X" -> 1 + 3
+        other == "A" && me == "Y" -> 2 + 6
+        other == "A" && me == "Z" -> 3 + 0
+        other == "B" && me == "X" -> 1 + 0
+        other == "B" && me == "Y" -> 2 + 3
+        other == "B" && me == "Z" -> 3 + 6
+        other == "C" && me == "X" -> 1 + 6
+        other == "C" && me == "Y" -> 2 + 0
+        other == "C" && me == "Z" -> 3 + 3
+        else -> throw IllegalArgumentException("should not happen")
+    }
+}
+
+fun scorePart2(other: String, me: String): Long {
+    return when {
+        other == "A" && me == "X" -> 3 + 0
+        other == "A" && me == "Y" -> 1 + 3
+        other == "A" && me == "Z" -> 2 + 6
+        other == "B" && me == "X" -> 1 + 0
+        other == "B" && me == "Y" -> 2 + 3
+        other == "B" && me == "Z" -> 3 + 6
+        other == "C" && me == "X" -> 2 + 0
+        other == "C" && me == "Y" -> 3 + 3
+        other == "C" && me == "Z" -> 1 + 6
+        else -> throw IllegalArgumentException("should not happen")
+    }
+}

src/main/kotlin/Day3.kt

@@ -0,0 +1,44 @@
+import java.io.File
+
+fun main() {
+    println("Hello day3!")
+    solveDay3()
+}
+
+fun solveDay3() {
+    val part1 = File("input/day3/input").readLines()
+        .map { solveRucksack1(it) }
+        .sum()
+    println(part1)
+
+    val part2 = File("input/day3/input").readLines()
+        .chunked(3)
+        .map { solveRucksack2(it) }
+        .sum()
+    println(part2)
+
+    // Part 2 again
+    println(File("input/day3/input").readLines()
+        .map { c -> c.toSet() }
+        .chunked(3)
+        .map { it.reduce { acc, s -> acc intersect s } }
+        .sumOf { prio(it.first()) }
+    )
+}
+
+fun solveRucksack1(content: String): Int {
+    val spitIndex = content.length / 2
+    val firstComp = content.substring(0, spitIndex).toSet()
+    val secondComp = content.substring(spitIndex).toSet()
+    val a = firstComp intersect secondComp
+    return prio(a.first())
+}
+
+fun solveRucksack2(content: List<String>): Int {
+    val a = content.map { c -> c.toSet() }.reduce { acc, it -> acc intersect it }
+    return prio(a.first())
+}
+
+fun prio(c: Char): Int {
+    return if (c.isLowerCase()) c.code - 96 else c.code - 38
+}