@NotNull
public Literal multiply(@NotNull Literal l, @NotNull Literal r) {
final Literal.Builder result = new Literal.Builder(l.getSize() + r.getSize());
final MutableInt li = new MutableInt();
final MutableInt ri = new MutableInt();
Productand lp = LiteralUtils.getNext(l, li);
Productand rp = LiteralUtils.getNext(r, ri);
while (lp != null || rp != null) {
final int c = LiteralUtils.compare(lp, rp);
if (c < 0) {
assert lp != null;
result.addProductand(lp);
lp = LiteralUtils.getNext(l, li);
} else if (c > 0) {
assert rp != null;
result.addProductand(rp);
rp = LiteralUtils.getNext(r, ri);
} else {
assert lp != null;
assert rp != null;
result.addProductand(lp.getVariable(), lp.getExponent() + rp.getExponent());
lp = LiteralUtils.getNext(l, li);
rp = LiteralUtils.getNext(r, ri);
}
}
return result.build();
}
