Day 3 part 1

main.go

@@ -10,8 +10,11 @@ func main() {
 	runAndBenchmark("01", "1", false, solutions.Day01Part01)
 	runAndBenchmark("01", "2", false, solutions.Day01Part02)
 
-	runAndBenchmark("02", "1", false, solutions.Day01Part01)
-	runAndBenchmark("02", "2", false, solutions.Day01Part02)
+	runAndBenchmark("02", "1", false, solutions.Day02Part01)
+	runAndBenchmark("02", "2", false, solutions.Day02Part02)
+
+	runAndBenchmark("03", "1", false, solutions.Day03Part01)
+	runAndBenchmark("03", "2", true, solutions.Day03Part02)
 }
 
 type execute func(bool) int

solutions/day03.go

@@ -0,0 +1,36 @@
+package solutions
+
+import "strings"
+
+func countTrees(input string, left, down int) int {
+	verticalPos := down
+	horizontalPos := left
+	lines := strings.Split(input, "\n")
+	width := len(lines[0])
+	treesCount := 0
+
+	for verticalPos < len(lines) {
+		line := lines[verticalPos]
+		charAt := string(line[horizontalPos])
+
+		if charAt == "#" {
+			treesCount += 1
+		}
+
+		horizontalPos += left
+		horizontalPos = horizontalPos % width
+		verticalPos += down
+	}
+
+	return treesCount
+}
+
+func Day03Part01(isTest bool) int {
+	input := ReadInput("03", isTest)
+
+	return countTrees(input, 3, 1)
+}
+
+func Day03Part02(isTest bool) int {
+	return -1
+}