distinct island

  /*
   start-> X;
   out of bound or 0-> O;
   left-> L
   right-> R
   down-> D
   up-> U
  */
  public static int numDistinctIslands(int[][] arr) {
    //write your code here
    if(arr== null || arr.length==0) return 0;
    HashSet<String> set= new HashSet<>();
    int m= arr.length;
    int n= arr[0].length;
    for(int i=0;i< m;i++){
        for(int j=0;j<n;j++){
            if(arr[i][j]==1){
                String curr= getDisitinctIslands(arr, i, j, m, n, "X");
                set.add(curr);
            } 
        }
    }
    return set.size();
  }
  
  public static String getDisitinctIslands(int[][] arr, int i, int j, int m, int n, String direction){
      if(i<0 || j<0 || i>=m || j>=n || arr[i][j]==0){
          return "O";
      }
      arr[i][j]=0;
      String up=getDisitinctIslands(arr, i-1, j, m, n, "U");
      String right=getDisitinctIslands(arr, i, j+1, m, n, "R");
      String down=getDisitinctIslands(arr, i+1, j, m, n, "D");
      String left=getDisitinctIslands(arr, i, j-1, m, n, "L");
      return direction+= up+ right+down+ left;
  }