Recursion의 응용 [Counting Cells in a Blob]

※ 문제 설명

      private static int BACKGROUND_PIXEL = 0;

       private static int IMAGE_PIXEL = 1;

       private static int VISITED_IMAGE_PIXCEL = 2;

       

       private static int[][] grid ={

                     {1,0,0,0,0,0,0,1},

                     {0,1,1,0,0,1,0,0},

                     {1,1,0,0,1,0,1,0},

                     {0,0,0,0,0,1,0,0},

                     {0,1,0,1,0,1,0,0},

                     {0,1,0,1,0,1,0,0},

                     {1,0,0,0,1,0,0,1},

                     {0,1,1,0,0,1,1,1}

       };

       

       public static void main(String[] args) {

              

              int x=0;

              int y=0;

              int blob =0;

              ArrayList<Integer> countList = new ArrayList<>();

              

              while( x != 7 || y != 7 ){

                     if(grid[x][y]==IMAGE_PIXEL){

                           countList.add(countCellinBlob(x, y));

                           blob ++;

                     }else{

                           if(y<7){

                                  y++;

                           }else{

                                  y=0;

                                  x++;

                           }

                     }

              }

              

              System.out.println("Blob의 수 : " + blob);

              System.out.println("각각의  Blob의 Size는 ");

              for(int i =0; i < countList.size(); i++){

                     System.out.print(countList.get(i));

                     if(i<countList.size()-1){

                           System.out.print(", ");

                     }

              }

              

       }

   

       public static int countCellinBlob(int x, int y){

              

              if(x<0 || x>7 || y<0 || y>7){

                     return 0;

              }

              else if(grid[x][y] == BACKGROUND_PIXEL || grid[x][y] == VISITED_IMAGE_PIXCEL){

                     return 0;

              }else{

                     grid[x][y] = VISITED_IMAGE_PIXCEL;

                     

                     return countCellinBlob(x,y+1) + countCellinBlob(x+1,y+1) + countCellinBlob(x+1,y)

                           + countCellinBlob(x+1,y-1) + countCellinBlob(x,y-1) + countCellinBlob(x-1,y-1)

                           + countCellinBlob(x-1,y) + countCellinBlob(x-1,y+1) + 1;

              }

       }