faster/better way to iterate blocks that are only in (bigger) one of two selections/squares

I have 2 squares -> selections
one is big, and second is smaller and is in bigger one, and I want iterate only over blocks that are in bigger one but isn't in smaller.

There is any better way than this loop?

Code:java

SquareSel big  = new SquareSel(new BlockPointer(-100, 0, -100, world), new BlockPointer(100, 256, 100));
SquareSel small = new SquareSel(new BlockPointer(-75, 10, -75, world), new BlockPointer(25, 200, 50));
 
for (int x = big.getMinPoint().getX(); x <= big.getMaxPoint().getX(); x++)
{
    for (int y = big.getMinPoint().getY(); y <= big.getMaxPoint().getY(); y++)
    {
        for (int z = big.getMinPoint().getZ(); z <= big.getMaxPoint().getZ(); z++)
        {
            if (small.contains(new BlockPointer(x, y, z, world)))
            {
                continue;
            }
            // do something with this block...
        }
    }
}

 

Smerfa I don't think there is. Any optimalization would probably occur around the checks themselves