static StringDoubleMap test(int n, int range) {
    // Generate random data
    Random rand = new Random();
    Set<Integer> set = new HashSet<Integer>();
    for (int i = 0; i < n; i++) set.add(rand.nextInt(range));

    // Make the map
    StringDoubleMap map = new StringDoubleMap(0);
    // map.switchToSortedList();
    for (int x : set) {
      map.put("" + x, 1.0 * x);
    }

    // System.out.println("here");
    check(set, map);
    map.switchToSortedList();
    check(set, map);
    map.switchToHashTable();
    check(set, map);

    map.lock();
    for (int x : set) map.put("" + x, 1.0 * x);

    assert set.size() == map.size();
    return map;
  }
 // Return a map with only keys in the set
 public StringDoubleMap restrict(Set<String> set) {
   StringDoubleMap newMap = new StringDoubleMap();
   newMap.mapType = mapType;
   if (mapType == MapType.SORTED_LIST) {
     newMap.allocate(getCapacity(num, false));
     for (int i = 0; i < keys.length; i++) {
       if (set.contains(keys[i])) {
         newMap.keys[newMap.num] = keys[i];
         newMap.values[newMap.num] = values[i];
         newMap.num++;
       }
     }
   } else if (mapType == MapType.HASH_TABLE) {
     for (int i = 0; i < keys.length; i++)
       if (keys[i] != null && set.contains(keys[i])) newMap.put(keys[i], values[i]);
   }
   newMap.locked = locked;
   return newMap;
 }
 static void check(Set<Integer> set, StringDoubleMap map) {
   for (int x : set) {
     double value = map.getSure("" + x);
     assert value == 1.0 * x;
   }
   for (StringDoubleMap.Entry e : map) {
     int x = Integer.parseInt(e.getKey());
     assert set.contains(x);
     assert e.getValue() == 1.0 * x;
   }
 }