2020 Day 3 Done!

2020/day03/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	inp := h.StdinToStringSlice()
+	total := 1
+	for _, slope := range []h.Coordinate{
+		{X: 1, Y: 1},
+		{X: 3, Y: 1},
+		{X: 5, Y: 1},
+		{X: 7, Y: 1},
+		{X: 1, Y: 2},
+	} {
+		field := h.StringSliceToCoordByteMap(inp)
+		val := countTrees(field, slope.X, slope.Y)
+		total = total * val
+		fmt.Println(slope.X, slope.Y, ":", val, "Trees")
+	}
+	fmt.Println("Total:", total)
+}
+
+func countTrees(field h.CoordByteMap, x, y int) int {
+	trees := 0
+	pos := h.Coordinate{X: x, Y: y}
+	for pos.Y < field.Height {
+		if pos.X > field.Width {
+			pos.X = pos.X - field.Width - 1
+		}
+		if field.Get(pos) == '#' {
+			trees++
+			field.Put(pos, 'X')
+		} else {
+			field.Put(pos, 'O')
+		}
+		pos.Y = pos.Y + y
+		pos.X = pos.X + x
+	}
+	return trees
+}