package main import ( "bufio" "fmt" "math" "os" "strconv" "strings" ) func main() { fmt.Println("Advent of Code 2025 - Day 9 - Part 1") f,_:= os.Open("9/input") defer f.Close() scanner:=bufio.NewScanner(f) var red_walls [][]int for scanner.Scan(){ line:= scanner.Text() line_sp := strings.Split(line, ",") x,_:= strconv.Atoi(line_sp[0]) y,_:= strconv.Atoi(line_sp[1]) red_walls = append(red_walls, []int{x,y}) } res := 0 for i:= range red_walls { w1:= red_walls[i] for j:= i+1; j < len(red_walls); j++{ w2:= red_walls[j] area := calculate_area(w1,w2) if area > res { res = area } } } fmt.Println(res) } func calculate_area(w1,w2 []int) int{ dx, dy := int(math.Abs(float64(w1[0]-w2[0]))), int(math.Abs(float64(w1[1]-w2[1]))) return (dx+1) * (dy+1) }