From c82509468ad6799b69fa46daec2e218fe594f6db Mon Sep 17 00:00:00 2001
From: chrisly42 <chrisly@platon42.de>
Date: Fri, 5 Dec 2025 06:21:02 +0100
Subject: [PATCH] Day 5.

---
 src/aoc2025/Day05.kt | 86 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 src/aoc2025/Day05.kt

diff --git a/src/aoc2025/Day05.kt b/src/aoc2025/Day05.kt
new file mode 100644
index 0000000..05655ae
--- /dev/null
+++ b/src/aoc2025/Day05.kt
@@ -0,0 +1,86 @@
+package aoc2025
+
+import println
+import readInput
+
+/*
+--- Day 5: Cafeteria ---
+https://adventofcode.com/2025/day/5
+*/
+fun main() {
+
+    val inlineTestInput = """
+3-5
+10-14
+16-20
+12-18
+
+1
+5
+8
+11
+17
+32
+"""
+
+    fun part1(input: List<String>): Int {
+        val ranges = ArrayList<LongRange>()
+        var freshNum = 0
+        for (i in input) {
+            if (i.contains("-")) {
+                val (low, high) = i.split("-").map { it.toLong() }
+                ranges.add(LongRange(low, high))
+            } else if (i.isNotBlank()) {
+                if (ranges.any { i.toLong() in it }) freshNum++
+            }
+        }
+        return freshNum
+    }
+
+    fun part2(input: List<String>): Long {
+        var freshSum = 0L
+        val ranges = ArrayList<LongRange>()
+        for (i in input) {
+            if (i.contains("-")) {
+                val (low, high) = i.split("-").map { it.toLong() }
+                ranges.add(LongRange(low, high))
+            }
+        }
+
+        val consolidated = ArrayList<LongRange>()
+        ranges.sortBy { it.first }
+        var lastLow = ranges[0].first
+        var lastHigh = ranges[0].last
+        for (r in 1..ranges.lastIndex) {
+            if (ranges[r].first > lastHigh) {
+                consolidated.add(LongRange(lastLow, lastHigh))
+                lastLow = ranges[r].first
+                lastHigh = ranges[r].last
+            } else {
+                lastHigh = lastHigh.coerceAtLeast(ranges[r].last)
+            }
+        }
+        consolidated.add(LongRange(lastLow, lastHigh))
+
+        for (r in consolidated) {
+            val e = r.last - r.first + 1
+            // had read that you should sum all of the IDs, then it would have been e * r.first + (e * e + 1) / 2
+            freshSum += e
+        }
+        return freshSum
+    }
+
+    // test if implementation meets criteria from the description, like:
+    val testInput = inlineTestInput.trim().reader().readLines()
+    //val testInput = readInput("aoc2025/Day05_test")
+    val testInputPart1Result = part1(testInput)
+    println("Part 1 Test: $testInputPart1Result")
+    val testInputPart2Result = part2(testInput)
+    println("Part 2 Test: $testInputPart2Result")
+    check(testInputPart1Result == 3)
+    check(testInputPart2Result == 14L)
+
+    val input = readInput("aoc2025/Day05")
+    part1(input).println()
+    part2(input).println()
+}