public void shuffle() {
T[] items = this.items;
for (int i = size - 1; i >= 0; i--) {
int ii = MathUtils.random(i);
T temp = items[i];
items[i] = items[ii];
items[ii] = temp;
}
}
public T random() {
if (size == 0) return null;
return items[MathUtils.random(0, size - 1)];
}
