Prepare for other years

2020-12-30 18:01:52 +01:00
parent 522618d106
commit 4a90257257
81 changed files with 277 additions and 253 deletions
@@ -0,0 +1,40 @@
+package be.vandewalleh.aoc.days
+
+import be.vandewalleh.aoc.utils.input.Day
+import be.vandewalleh.aoc.utils.input.Input
+import be.vandewalleh.aoc.utils.input.Lines
+
+@Day(3)
+class Day03(@Lines val input: Input<List<String>>) {
+    private data class Slope(val x: Int, val y: Int)
+
+    private fun findSlope(slope: Slope): Int {
+        val grid = input.value
+        var trees = 0
+        var x = 0
+        var y = 0
+
+        val width = grid.first().length
+
+        while (y < grid.size - 1) {
+            x += slope.x
+            y += slope.y
+
+            if (grid[y][x % width] == '#') trees++
+        }
+
+        return trees
+    }
+
+    fun part1() = findSlope(Slope(x = 3, y = 1))
+
+    fun part2(): Long = listOf(
+        Slope(x = 1, y = 1),
+        Slope(x = 3, y = 1),
+        Slope(x = 5, y = 1),
+        Slope(x = 7, y = 1),
+        Slope(x = 1, y = 2),
+    )
+        .map { findSlope(it).toLong() }
+        .reduce { acc, trees -> acc * trees }
+}