Update solution

advent-of-code-2023/src/main/kotlin/Solution05.kt

@@ -1,6 +1,6 @@
 class Solution05(lines: List<String>) {
     private var seeds: MutableList<ULong> = mutableListOf()
-    private var maps: MutableMap<String, Ranges> = mutableMapOf()
+    private var maps: MutableList<MapList> = mutableListOf()
 
     init {
         // Parse seeds
@@ -8,24 +8,16 @@ class Solution05(lines: List<String>) {
         seeds.addAll(seedsStr.split(" ").map{it.toULong()})
 
         // Parse all maps
-        var currentSrc = ""
         for (line in lines.subList(2, lines.size)) {
             if (line.isEmpty()) continue
 
             if (line.contains(" map:")) {
-                val (mapTitle, _) = line.split(" ")
-                val (src, dest) = mapTitle.split("-to-")
-                currentSrc = src
-
-                if (!maps.containsKey(currentSrc)) {
-                    maps[currentSrc] = Ranges(dest)
-                }
-
+                maps.add(MapList())
                 continue
             }
 
             val (destRangeStart, srcRangeStart, rangeLength) = line.split(" ")
-            maps[currentSrc]?.addRange(
+            maps.last().addRange(
                 srcRangeStart.toULong(),
                 destRangeStart.toULong(),
                 rangeLength.toULong(),
@@ -33,52 +25,63 @@ class Solution05(lines: List<String>) {
         }
     }
 
+    // Part 1.
     fun getLowestLocationNumber(): ULong {
         return seeds
-            .map{convertSeedNumber(it, "location")}
+            .map{
+                var num = it
+
+                for (map in maps) {
+                    num = map.mapSrcNumberToDest(num)
+                }
+
+                num
+            }
             .min()
     }
 
+    // Part 2.
     fun getLowestLocationNumberForRangeOfSeeds(): ULong {
-        val allSeeds: MutableSet<ULong> = mutableSetOf()
+        // Available location numbers.
+        var currentRanges = maps
+            .last()
+            .mappers
+            .map{RangeFromLoc(it.destRangeStart, it.rangeLength, it.destRangeStart)}
+
+        for (map in maps.reversed()) {
+            val newList: MutableList<RangeFromLoc> = mutableListOf()
+
+            for (mapper in map.mappers) {
+                // Find intersections
+                currentRanges
+
+
+                for (rng in currentRanges) {
 
-        for (i in 0..<seeds.size step 2) {
-            for (j in seeds[i]..<seeds[i]+seeds[i+1]) {
-                allSeeds.add(j)
                 }
             }
 
-        return allSeeds
-            .map{convertSeedNumber(it, "location")}
-            .min()
+            currentRanges = newList
         }
 
-    private fun convertSeedNumber(seed: ULong, target: String): ULong {
-        var dest = "seed"
-
-        var num = seed
-
-        while (dest != target) {
-            val ranges = maps[dest]!!
-            dest = ranges.destName
-            num = ranges.mapNumber(num)
-        }
-
-        return num
+        return 0UL
     }
 }
 
-data class Ranges(val destName: String) {
-    val ranges: MutableList<Range> = mutableListOf()
+// Map stores the rules for matching one number to another.
+class MapList() {
+    val mappers: MutableList<Mapper> = mutableListOf()
 
     fun addRange(sourceRangeStart: ULong, destRangeStart: ULong, rangeLength: ULong) {
-        ranges.add(Range(sourceRangeStart, destRangeStart, rangeLength))
+        mappers.add(
+            Mapper(sourceRangeStart, destRangeStart, rangeLength),
+        )
     }
 
-    fun mapNumber(src: ULong): ULong {
-        for (range in ranges) {
-            if (src >= range.sourceRangeStart && src < range.sourceRangeStart + range.rangeLength) {
-                return range.destRangeStart + src - range.sourceRangeStart
+    fun mapSrcNumberToDest(src: ULong): ULong {
+        for (range in mappers) {
+            if (range.isNumberInSrcRange(src)) {
+                return range.srcValueToDest(src)
             }
         }
 
@@ -86,4 +89,20 @@ data class Ranges(val destName: String) {
     }
 }
 
-data class Range(val sourceRangeStart: ULong, val destRangeStart: ULong, val rangeLength: ULong)
+// Mapper contains one line of map.
+data class Mapper(val sourceRangeStart: ULong, val destRangeStart: ULong, val rangeLength: ULong) {
+    fun srcValueToDest(v: ULong): ULong {
+        return destRangeStart + v - sourceRangeStart
+    }
+
+    fun isNumberInSrcRange(num: ULong): Boolean {
+        return num >= sourceRangeStart && num < sourceRangeStart + rangeLength
+    }
+}
+
+// Range of numbers with the first number of corresponding location.
+data class RangeFromLoc(val rangeStart: ULong, val rangeLength: ULong, val locationStart: ULong) {
+    fun getIntersection(newRangeStart: ULong, newRangeLength: ULong): RangeFromLoc {
+        return RangeFromLoc(rangeStart, rangeLength, locationStart)
+    }
+}

advent-of-code-2023/src/test/kotlin/Solution05Test.kt

@@ -13,7 +13,7 @@ class Solution05Test {
     fun solvePart1() {
         val text = ResourceReader().readFile("day-05/input.txt")
         val res = Solution05(text).getLowestLocationNumber()
-        println(res)
+        assertEquals(621354867UL, res)
     }
 
     @Test