package main import ( "bufio" "fmt" "log" "os" ) type Point struct { x, y int } func (p *Point) key() string { return fmt.Sprintf("%d_%d", p.y, p.x) } func readInput(file *os.File) (map[byte][]Point, [][]byte) { scanner := bufio.NewScanner(file) var matrix [][]byte groups := make(map[byte][]Point) var y int for scanner.Scan() { line := scanner.Text() if line == "" { break } matrix = append(matrix, []byte(line)) for x := range line { if line[x] != '.' { groups[line[x]] = append(groups[line[x]], Point{x: x, y: y}) } } y++ } return groups, matrix } func main() { if len(os.Args) < 2 { log.Fatal("You need to specify a file!") } filePath := os.Args[1] file, err := os.Open(filePath) if err != nil { log.Fatalf("Failed to open %s!\n", filePath) } groups, matrix := readInput(file) fmt.Println(groups, matrix) }