| 8 | } |
| 9 | |
| 10 | public void change(int index, int number) { |
| 11 | // delete old |
| 12 | if(idxToNumber.containsKey(index)){ |
| 13 | int prev = idxToNumber.get(index); |
| 14 | numberToIdx.get(prev).remove(index); |
| 15 | if(numberToIdx.get(prev).size()==0){ |
| 16 | numberToIdx.remove(prev); |
| 17 | } |
| 18 | } |
| 19 | // insert new |
| 20 | idxToNumber.put(index,number); |
| 21 | if(!numberToIdx.containsKey(number)){ |
| 22 | numberToIdx.put(number, new TreeSet<>()); |
| 23 | } |
| 24 | numberToIdx.get(number).add(index); |
| 25 | } |
| 26 | |
| 27 | public int find(int number) { |
| 28 | if(!numberToIdx.containsKey(number)){ |