code: public static int[] setSteps(Last[][][] traceback, int[] xyMax, List<Step> sx, List<Step> sy) {
  		return setSteps(traceback, true, xyMax, Last.SUBSTITUTION, sx, sy);
  	}
docs: Find local alignment path through traceback matrix
  @param traceback
  @param xyMax
  @param sx
  @param sy
  @return