Integer.signum(indexSize % interval);
IntSet[] tails = new IntSet[precalcSize];
IntSet currentTail = IntSetBuilder.newEmptyIntSet(numKeyValues);
for (int i = indexSize - 1; i >= 0; i--) {
currentTail = currentTail.unite(valueStore[i]);
if (i % interval == 0) {
tails[i / interval] = currentTail;
currentTail = currentTail.clone();
}
}