Day 6

src/main/kotlin/com/basdado/adventofcode/Day6.kt

@@ -0,0 +1,105 @@
+package com.basdado.adventofcode
+
+import java.util.*
+import java.util.Arrays.stream
+import java.util.stream.Collectors
+import kotlin.math.abs
+
+fun main() {
+
+    val day = Day6()
+    day.puzzle1()
+    day.puzzle2()
+}
+
+class Day6 {
+
+    fun puzzle1() {
+
+        val coords = lines("/day/6/input.txt")
+            .map { it.split(",") }
+            .map { Pair(it[0].trim().toInt(), it[1].trim().toInt()) }
+            .collect(Collectors.toList())
+
+        val minX = coords.stream().mapToInt { it.first }.min().asInt - 1
+        val maxX = coords.stream().mapToInt { it.first }.max().asInt + 1
+        val minY = coords.stream().mapToInt { it.second }.min().asInt - 1
+        val maxY = coords.stream().mapToInt { it.second }.max().asInt + 1
+
+        val grid = Array(maxY - minY) { Array(maxX - minX) { Cell(-1, Int.MAX_VALUE) } }
+
+        for (areaId in 0 until coords.size) {
+
+            val areaCenter = coords[areaId]
+            for(y in minY until maxY) {
+                val j = y - minY
+                for (x in minX until maxX) {
+                    val i = x - minX
+
+                    val dist = abs(areaCenter.first - x) + abs(areaCenter.second - y)
+                    if (dist < grid[j][i].minDistance) {
+                        grid[j][i].minDistance = dist
+                        grid[j][i].minAreaId = areaId
+                    } else if (dist == grid[j][i].minDistance) {
+                        // Equal distance so this doesn't count
+                        grid[j][i].minAreaId = -1
+                    }
+                }
+            }
+        }
+
+//        println(Arrays.stream(grid).map { Arrays.stream(it).map { it.minAreaId.toString() }.collect(Collectors.joining(" "))}.collect(Collectors.joining("\r\n")))
+
+        val infiniteAreas = HashSet<Int>()
+        infiniteAreas.add(-1)
+        stream(grid[0]).map { it.minAreaId }.collect(Collectors.toSet())
+        infiniteAreas.addAll(stream(grid[grid.size - 1]).map { it.minAreaId }.collect(Collectors.toSet()))
+        infiniteAreas.addAll(stream(grid).map { it[0].minAreaId }.collect(Collectors.toSet()))
+        infiniteAreas.addAll(stream(grid).map { it[it.size - 1].minAreaId }.collect(Collectors.toSet()))
+
+        val areaSizes = stream(grid)
+            .flatMap { stream(it) }
+            .filter{ !infiniteAreas.contains(it.minAreaId) }
+            .collect(Collectors.groupingBy({ c: Cell -> c.minAreaId }, Collectors.counting()))
+
+        println(areaSizes.values.max())
+    }
+
+    fun puzzle2() {
+
+        val coords = lines("/day/6/input.txt")
+            .map { it.split(",") }
+            .map { Pair(it[0].trim().toInt(), it[1].trim().toInt()) }
+            .collect(Collectors.toList())
+
+        val minX = coords.stream().mapToInt { it.first }.min().asInt - 1
+        val maxX = coords.stream().mapToInt { it.first }.max().asInt + 1
+        val minY = coords.stream().mapToInt { it.second }.min().asInt - 1
+        val maxY = coords.stream().mapToInt { it.second }.max().asInt + 1
+
+        val grid = Array(maxY - minY) { Array(maxX - minX) { 0 } }
+
+        for(y in minY until maxY) {
+            val j = y - minY
+            for (x in minX until maxX) {
+                val i = x - minX
+
+                for (areaId in 0 until coords.size) {
+
+                    val areaCenter = coords[areaId]
+
+                    grid[j][i] += abs(areaCenter.first - x) + abs(areaCenter.second - y)
+                }
+            }
+        }
+
+        println(stream(grid)
+            .flatMapToInt { stream(it).mapToInt{i -> i} }
+            .filter{ it < 10000 }
+            .boxed()
+            .collect(Collectors.counting()))
+    }
+
+    data class Cell (var minAreaId: Int, var minDistance: Int)
+
+}

src/main/resources/day/6/input.txt

@@ -0,0 +1,50 @@
+177, 51
+350, 132
+276, 139
+249, 189
+225, 137
+337, 354
+270, 147
+182, 329
+118, 254
+174, 280
+42, 349
+96, 341
+236, 46
+84, 253
+292, 143
+253, 92
+224, 137
+209, 325
+243, 195
+208, 337
+197, 42
+208, 87
+45, 96
+64, 295
+266, 248
+248, 298
+194, 261
+157, 74
+52, 248
+243, 201
+242, 178
+140, 319
+69, 270
+314, 302
+209, 212
+237, 217
+86, 294
+295, 144
+248, 206
+157, 118
+155, 146
+331, 40
+247, 302
+250, 95
+193, 214
+345, 89
+183, 206
+121, 169
+79, 230
+88, 155