Merge pull request #6 from jwnace/day03-add-tests

added tests for day 3

src/main/kotlin/day03/PartNumber.kt

@@ -7,7 +7,7 @@ data class PartNumber(val number: Int, val row: Int, val startCol: Int, val endC
 
     fun isAdjacentTo(position: Pair<Int, Int>) =
         row >= position.first - 1 &&
-                row <= position.first + 1 &&
-                endCol >= position.second - 1 &&
-                startCol <= position.second + 1
+        row <= position.first + 1 &&
+        endCol >= position.second - 1 &&
+        startCol <= position.second + 1
 }

src/main/kotlin/day03/day03.kt

@@ -0,0 +1,81 @@
+package day03
+
+import java.io.File
+
+val input = File("src/main/kotlin/day03/input.txt").readLines()
+
+fun solve1() = part1(input)
+
+fun solve2() = part2(input)
+
+fun part1(input: List<String>): Int {
+    val grid = buildGrid(input)
+    val partNumbers = getPartNumbers(grid)
+
+    return partNumbers.sumOf { it.number }
+}
+
+fun part2(input: List<String>): Int {
+    val grid = buildGrid(input)
+    val partNumbers = getPartNumbers(grid)
+
+    return grid.filter { it.value.isSymbol() }
+        .filter { symbol -> symbolIsAdjacentToTwoPartNumbers(partNumbers, symbol) }
+        .map { symbol -> getAdjacentPartNumbers(partNumbers, symbol) }
+        .sumOf { it[0].number * it[1].number }
+}
+
+fun buildGrid(input: List<String>): Map<Pair<Int, Int>, Char> {
+    val grid = mutableMapOf<Pair<Int, Int>, Char>()
+
+    for (row in input.indices) {
+        for (col in input[row].indices) {
+            grid[Pair(row, col)] = input[row][col]
+        }
+    }
+
+    return grid
+}
+
+fun getPartNumbers(grid: Map<Pair<Int, Int>, Char>): List<PartNumber> {
+    val partNumbers = mutableListOf<PartNumber>()
+    val maxRow = grid.maxOf { it.key.first }
+    val maxCol = grid.maxOf { it.key.second }
+
+    for (row in 0..maxRow) {
+        var col = 0
+
+        while (col <= maxCol) {
+            var currentNumber = 0
+            var startCol = 0
+            var endCol = 0
+
+            while (grid[Pair(row, col)]?.isDigit() == true) {
+                if (currentNumber == 0) {
+                    currentNumber = grid[Pair(row, col)]!!.digitToInt()
+                    startCol = col
+                    endCol = col
+                } else {
+                    currentNumber = currentNumber * 10 + grid[Pair(row, col)]!!.digitToInt()
+                    endCol = col
+                }
+
+                col++
+            }
+
+            if (currentNumber != 0) {
+                partNumbers.add(PartNumber(currentNumber, row, startCol, endCol))
+            }
+
+            col++
+        }
+    }
+
+    return partNumbers.filter { it.isAdjacentToSymbol(grid) }
+}
+
+fun symbolIsAdjacentToTwoPartNumbers(partNumbers: List<PartNumber>, symbol: Map.Entry<Pair<Int, Int>, Char>) =
+    partNumbers.count { it.isAdjacentTo(symbol.key) } == 2
+
+fun getAdjacentPartNumbers(partNumbers: List<PartNumber>, symbol: Map.Entry<Pair<Int, Int>, Char>) =
+    partNumbers.filter { it.isAdjacentTo(symbol.key) }

src/main/kotlin/main.kt

@@ -1,4 +1,8 @@
 fun main() {
     println("day 01, part 1: ${day01.solve1()}")
     println("day 01, part 2: ${day01.solve2()}")
+    println("day 02, part 1: ${day02.solve1()}")
+    println("day 02, part 2: ${day02.solve2()}")
+    println("day 03, part 1: ${day03.solve1()}")
+    println("day 03, part 2: ${day03.solve2()}")
 }

src/test/kotlin/day03/Day03Tests.kt

@@ -0,0 +1,62 @@
+package day03
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+class Day03Tests {
+    @Test
+    fun `part1 example`() {
+        // arrange
+        val input = listOf(
+            "467..114..",
+            "...*......",
+            "..35..633.",
+            "......#...",
+            "617*......",
+            ".....+.58.",
+            "..592.....",
+            "......755.",
+            "...$.*....",
+            ".664.598..",
+        )
+
+        // act
+        val actual = part1(input)
+
+        // assert
+        assertEquals(4361, actual)
+    }
+
+    @Test
+    fun `part1 solution`() {
+        assertEquals(514969, solve1())
+    }
+
+    @Test
+    fun `part2 example`() {
+        // arrange
+        val input = listOf(
+            "467..114..",
+            "...*......",
+            "..35..633.",
+            "......#...",
+            "617*......",
+            ".....+.58.",
+            "..592.....",
+            "......755.",
+            "...$.*....",
+            ".664.598..",
+        )
+
+        // act
+        val actual = part2(input)
+
+        // assert
+        assertEquals(467835, actual)
+    }
+
+    @Test
+    fun `part2 solution`() {
+        assertEquals(78915902, solve2())
+    }
+}