2023 - Day 13 - part 1

fmmr · Dec 13, 2023 · bb0b06f · bb0b06f
1 parent d3ea6d4
commit bb0b06f
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Showing 2 changed files with 73 additions and 8 deletions.
diff --git a/src/main/kotlin/no/rodland/advent_2023/Day13.kt b/src/main/kotlin/no/rodland/advent_2023/Day13.kt
@@ -5,23 +5,87 @@ import no.rodland.advent.Day
 // template generated: 13/12/2023
 // Fredrik Rødland 2023
 
-class Day13(val input: List<String>) : Day<Long, Long, List<String>> {
+class Day13(val input: List<String>) : Day<Int, Long, List<Day13.GroundMap>> {
 
     private val parsed = input.parse()
 
-    override fun partOne(): Long {
-        return 2
+    override fun partOne(): Int {
+        return parsed.map { groundMap ->
+            val rowsHorizontal = isMirror(groundMap)
+            val rowsVertical = if (rowsHorizontal == 0) {
+                isMirror(groundMap.transpose())
+            } else {
+                0
+            }
+//            debug(rowsVertical, rowsHorisontal, groundMap)
+            rowsVertical + 100 * rowsHorizontal
+        }.sum()
+    }
+
+    private fun debug(rowsVertical: Int, rowsHorisontal: Int, groundMap: GroundMap) {
+        if (rowsVertical == 0 && rowsHorisontal == 0) {
+            println("no reflection for:")
+        } else {
+            println("misc v: $rowsVertical, h: $rowsHorisontal")
+        }
+        groundMap.print()
+        println()
+    }
+
+    // 1500 too low
+    // 1700 too low
+    private fun isMirror(groundMap: GroundMap): Int {
+        (1..<groundMap.size).forEach { i ->
+            val map = groundMap.grounds
+
+            val rev = map.subList(0, i).asReversed()
+            val forw = map.subList(i, map.size)
+
+            val size = minOf(rev.size, forw.size)
+            // println("rev:   $rev    for:    $forw")
+            if (rev.subList(0, size) == forw.subList(0, size))
+                return i
+        }
+        return 0
     }
 
     override fun partTwo(): Long {
         return 2
     }
 
-    override fun List<String>.parse(): List<String> {
-        return map { line ->
-            line
+    override fun List<String>.parse(): List<GroundMap> {
+        val converters = joinToString("\n").split("\n\n").map { it.split("\n") }
+
+        return converters.map { l ->
+            GroundMap(l)
+        }
+
+    }
+
+    data class GroundMap(val grounds: List<String>) {
+        fun transpose() = GroundMap(grounds.transpose())
+        val size = grounds.size
+        val reversed = grounds.reversed()
+
+        fun print() {
+            grounds.map { line ->
+                println(line)
+            }
+
         }
     }
 
     override val day = "13".toInt()
 }
+
+private fun List<String>.transpose(): List<String> {
+    val width = first().length
+    val height = size
+    return (0..<width).map { j ->
+        (0..<height).map { i ->
+            get(i)[j]
+        }.joinToString("")
+    }
+}
+
+
diff --git a/src/test/kotlin/no/rodland/advent_2023/Day13Test.kt b/src/test/kotlin/no/rodland/advent_2023/Day13Test.kt
@@ -15,9 +15,9 @@ internal class Day13Test {
     private val data13 = "2023/input_13.txt".readFile()
     private val test13 = "2023/input_13_test.txt".readFile()
 
-    private val resultTestOne = 2L
+    private val resultTestOne = 405
     private val resultTestTwo = 2L
-    private val resultOne = 2L
+    private val resultOne = 40006
     private val resultTwo = 2L
 
     val test = defaultTestSuiteParseOnInit(
@@ -29,6 +29,7 @@ internal class Day13Test {
         resultTwo,
         { Day13(data13) },
         { Day13(test13) },
+        numTestPart1 = 300
     )
 
     @Nested