Adjacent spaces

[slidingtile] / sliding_tile.go

diff --git a/sliding_tile.go b/sliding_tile.go
index a934b4e055f6594da8c7e1f9a5b3243d1108ae68..96e00dcc85645a6d997a878028adf06bf42e4af6 100644 (file)
--- a/sliding_tile.go
+++ b/sliding_tile.go
@@ -5,30 +5,58 @@ import "os"
 import "strconv"
 
 const HOLE = 0
-const BOARD_SIZE = 16
+const BOARD_DIM = 4
+const BOARD_SIZE = BOARD_DIM * BOARD_DIM
 
 type Space int8
 type Board [BOARD_SIZE]Space
 
+const (
+       LEFT  = -1
+       RIGHT = +1
+       UP    = -BOARD_DIM
+       DOWN  = +BOARD_DIM
+)
+
 func read_board_from_strings(in []string) (*Board, error) {
-  if len(in) != BOARD_SIZE {
-    return nil, fmt.Errorf("Please provide %d values", BOARD_SIZE)
-  }
-  var b Board
-  for i, s := range in {
-    num, err := strconv.Atoi(s)
-    b[i] = Space(num)
-    if err != nil {
-      return nil, err
-    }
-  }
-  return &b, nil
+       if len(in) != BOARD_SIZE {
+               return nil, fmt.Errorf("Please provide %d values", BOARD_SIZE)
+       }
+       var b Board
+       for i, s := range in {
+               num, err := strconv.Atoi(s)
+               b[i] = Space(num)
+               if err != nil {
+                       return nil, err
+               }
+       }
+       return &b, nil
+}
+
+func adjacent_spaces(s Space) []Space {
+       if s < 0 || s >= BOARD_SIZE {
+               panic("Invalid space")
+       }
+       var adjacent []Space
+       if s >= BOARD_DIM {
+               adjacent = append(adjacent, s+UP)
+       }
+       if s < BOARD_SIZE-BOARD_DIM {
+               adjacent = append(adjacent, s+DOWN)
+       }
+       if s%BOARD_DIM != 0 {
+               adjacent = append(adjacent, s+LEFT)
+       }
+       if s%BOARD_DIM != BOARD_DIM-1 {
+               adjacent = append(adjacent, s+RIGHT)
+       }
+       return adjacent
 }
 
 func main() {
-  start, err := read_board_from_strings(os.Args[1:])
-  if err != nil {
-    panic(err)
-  }
-  fmt.Println(start)
+       start, err := read_board_from_strings(os.Args[1:])
+       if err != nil {
+               panic(err)
+       }
+       fmt.Println(start)
 }