Solved for small input

08/code.go

@@ -23,6 +23,90 @@ func readInput(file *os.File) [][]byte {
 	return trees
 }
 
+func visibleFromLeft(x int, y int, trees [][]byte) bool {
+	visible := true
+	for i := 0; i < x; i++ {
+		if trees[y][i] >= trees[y][x] {
+			visible = false
+			break
+		}
+	}
+
+	return visible
+}
+
+func visibleFromRight(x int, y int, trees [][]byte, limit int) bool {
+	visible := true
+	for i := x + 1; i < limit; i++ {
+		if trees[y][i] >= trees[y][x] {
+			visible = false
+			break
+		}
+	}
+
+	return visible
+}
+
+func visibleFromTop(x int, y int, trees [][]byte) bool {
+	visible := true
+	for i := 0; i < y; i++ {
+		if trees[i][x] >= trees[y][x] {
+			visible = false
+			break
+		}
+	}
+
+	return visible
+}
+
+func visibleFromBottom(x int, y int, trees [][]byte, limit int) bool {
+	visible := true
+	for i := x + 1; i < limit; i++ {
+		if trees[i][x] >= trees[y][x] {
+			visible = false
+			break
+		}
+	}
+
+	return visible
+}
+
+func isVisible(x int, y int, trees [][]byte, width int, height int) bool {
+	if visibleFromLeft(x, y, trees) {
+		return true
+	}
+
+	if visibleFromRight(x, y, trees, width) {
+		return true
+	}
+
+	if visibleFromTop(x, y, trees) {
+		return true
+	}
+
+	if visibleFromBottom(x, y, trees, height) {
+		return true
+	}
+
+	return false
+}
+
+func part1(trees [][]byte) int {
+	width := len(trees[0])
+	height := len(trees)
+
+	visible := 2*height + (width-2)*2
+	for y := 1; y < height-1; y++ {
+		for x := 1; x < width-1; x++ {
+			if isVisible(x, y, trees, width, height) {
+				visible++
+			}
+		}
+	}
+
+	return visible
+}
+
 func main() {
 	if len(os.Args) < 2 {
 		log.Fatal("You need to specify a file!")
@@ -36,5 +120,5 @@ func main() {
 	}
 
 	trees := readInput(file)
-	fmt.Println(trees)
+	fmt.Println("Part1:", part1(trees))
 }