Add 2021 - Day 2 - Part 2

2021/02/main.kt

@@ -4,6 +4,16 @@ fun main() {
 	val lines = File("input/1.txt").readLines()
 	val directions = lines.map { line -> line.split(' ', limit = 2).let { it[0] to it[1].toInt() } }
 	
+	println("Part 1:")
+	part1(directions)
+	
+	println()
+	
+	println("Part 2:")
+	part2(directions)
+}
+
+private fun part1(directions: List<Pair<String, Int>>) {
 	var position = 0
 	var depth = 0
 	
@@ -19,3 +29,24 @@ fun main() {
 	println("Depth: $depth")
 	println("Multiplied: ${position * depth}")
 }
+
+private fun part2(directions: List<Pair<String, Int>>) {
+	var position = 0
+	var depth = 0
+	var aim = 0
+	
+	for ((direction, distance) in directions) {
+		when (direction) {
+			"forward" -> {
+				position += distance
+				depth += aim * distance
+			}
+			"up"      -> aim -= distance
+			"down"    -> aim += distance
+		}
+	}
+	
+	println("Position: $position")
+	println("Depth: $depth")
+	println("Multiplied: ${position * depth}")
+}

README.md

@@ -31,3 +31,4 @@ The versions should not matter, but I used Visual Studio 2019 with `MSVC v142 (1
 |-----:|----:|----------|
 | 2015 |  01 | NASM x86 |
 | 2021 |  01 | Kotlin   |
+| 2021 |  02 | Kotlin   |