Aquarium

Hard Aquarium — what to expect

Hard Aquarium uses 10×10 grids with 8 to 12 aquariums, some of them irregularly shaped. Over/under counting becomes a real technique: before committing to a water level, check whether that level would push any shared row or column past its target. Several aquariums will have multiple plausible levels, and you need to find the one that satisfies all constraints simultaneously.