sclass SimpleIntList extends RandomAccessAbstractList<Int> {
  int[] data = EMPTY_ELEMENTDATA;
  int size;
  
  private static final int[] EMPTY_ELEMENTDATA = {};

  public void add(int i) {
    ensureCapacityInternal(size+1);
    data[size++] = i;
  }
  
  public bool add(Int i) {
    add((int) i);
    true;
  }
  
  public Int set(int i, Int value) {
    if (i >= size) fail("Index out of range: " + i);
    int old = data[i];
    data[i] = value;
    ret old;
  }
  
  public int size() { ret size; }
  
  public Int get(int i) {
    if (i >= 0 && i < size) ret data[i];
    throw new IndexOutOfBoundsException(i + "/" + size);
  }
  
  void ensureCapacityInternal(int minCapacity) {
    if (data.length < minCapacity) grow(minCapacity);
  }
  
  private void grow(int minCapacity) {
    int oldCapacity = data.length;
    int newCapacity = oldCapacity + (oldCapacity >> 1);
    if (newCapacity - minCapacity < 0)
      newCapacity = minCapacity;
    data = Arrays.copyOf(data, newCapacity);
  }
  
  // always returns a fresh copy
  int[] toIntArray() {
    int[] a = new int[size];
    System.arraycopy(data, 0, a, 0, size);
    ret a;
  }
}