Move year 2021 into a subfolder

1 files changed, 56 insertions, 0 deletions

diff --git a/2021-kotlin/src/Day02.kt b/2021-kotlin/src/Day02.kt
new file mode 100644
index 0000000..2eb085a
--- /dev/null
+++ b/2021-kotlin/src/Day02.kt
@@ -0,0 +1,56 @@
+object Day02 {
+    private fun dispatchCommands(commands: List<String>, action: (command: String, argument: Int) -> Unit) {
+        for (line in commands) {
+            val parts = line.split(" ")
+            val command = parts[0]
+            val argument = parts[1].toInt()
+
+            action(command, argument)
+        }
+    }
+
+    fun part1(input: List<String>): Int {
+        var horizontal = 0
+        var depth = 0
+
+        dispatchCommands(input) { command, argument ->
+            when (command) {
+                "forward" -> horizontal += argument
+                "down" -> depth += argument
+                "up" -> depth -= argument
+            }
+        }
+
+        return horizontal * depth
+    }
+
+    fun part2(input: List<String>): Int {
+        var horizontal = 0
+        var depth = 0
+        var aim = 0
+
+        dispatchCommands(input) { command, argument ->
+            when (command) {
+                "forward" -> {
+                    horizontal += argument
+                    depth += aim * argument
+                }
+
+                "down" -> aim += argument
+                "up" -> aim -= argument
+            }
+        }
+
+        return horizontal * depth
+    }
+}
+
+fun main() {
+    val testInput = readInputAsLines("Day02_test")
+    check(Day02.part1(testInput) == 150)
+    check(Day02.part2(testInput) == 900)
+
+    val input = readInputAsLines("Day02")
+    println(Day02.part1(input))
+    println(Day02.part2(input))
+}