package main import ( "bufio" "fmt" "os" "strconv" "strings" "time" ) func mustAtoi(line string) int { i, _ := strconv.Atoi(line) return i } func main() { start := time.Now() partOne() duration := time.Since(start) partTwo() duration2 := time.Since(start) fmt.Printf("p1: %s, p2: %s\n", duration, duration2-duration) } func makeScanner(test bool) *bufio.Scanner { var f *os.File if test { f, _ = os.Open("inputs/testinput") } else { f, _ = os.Open("inputs/input") } reader := bufio.NewReader(f) return bufio.NewScanner(reader) } type point struct { x int y int } func partOne() { scanner := makeScanner(false) // parse points points := make(map[point]struct{}, 0) for scanner.Scan() { line := scanner.Text() if line == "" { break } p := strings.Split(line, ",") points[point{ x: mustAtoi(p[0]), y: mustAtoi(p[1]), }] = struct{}{} } // make first fold scanner.Scan() f := strings.Split(scanner.Text(), "=") orientation := strings.Split(f[0], " ")[2] crease := mustAtoi(f[1]) if orientation == "y" { for p := range points { if p.y > crease { delete(points, p) points[point{x: p.x, y: p.y - ((p.y - crease) * 2)}] = struct{}{} } } } if orientation == "x" { for p := range points { if p.x > crease { delete(points, p) points[point{x: p.x - ((p.x - crease) * 2), y: p.y}] = struct{}{} } } } fmt.Println(len(points)) } func partTwo() { scanner := makeScanner(false) // parse points points := make(map[point]struct{}, 0) for scanner.Scan() { line := scanner.Text() if line == "" { break } p := strings.Split(line, ",") points[point{ x: mustAtoi(p[0]), y: mustAtoi(p[1]), }] = struct{}{} } // do folds for scanner.Scan() { line := scanner.Text() f := strings.Split(line, "=") orientation := strings.Split(f[0], " ")[2] crease := mustAtoi(f[1]) if orientation == "y" { for p := range points { if p.y > crease { delete(points, p) points[point{x: p.x, y: p.y - ((p.y - crease) * 2)}] = struct{}{} } } } if orientation == "x" { for p := range points { if p.x > crease { delete(points, p) points[point{x: p.x - ((p.x - crease) * 2), y: p.y}] = struct{}{} } } } } // print letters for y := 0; y < 6; y++ { // six units tall for x := 0; x < 5*8; x++ { // 5 units wide, 8 letters if _, ok := points[point{x: x, y: y}]; ok { fmt.Printf("#") } else { fmt.Printf(" ") } } fmt.Printf("\n") } }