code: private void sortArrayList(List<InvPair> v) {
          Collections.sort(v, new Comparator<InvPair>() {
  
              @Override
              public int compare(InvPair o1, InvPair o2) {
                  if (o1.getCurr() > o2.getCurr()) return +1;
                  if (o1.getCurr() < o2.getCurr()) return -1;
                  return 0;
              }
          });
          Collections.sort(v, new Comparator<InvPair>() {
  
              @Override
              public int compare(InvPair o1, InvPair o2) {
                  if (o1.getLast() > o2.getLast()) return +1;
                  if (o1.getLast() < o2.getLast()) return -1;
                  return 0;
              }
          });
      }
docs: Sorts the vector according to the current invariance, corresponds to step 3
  
  @param v the invariance pair vector
  @cdk.todo    can this be done in one loop?