Puzzle 30 / Fillomino [Skyscrapers]

Haha, way-overdue Fillomino-Fillia practice puzzle. This is a Fillomino puzzle; in addition to normal rules, treat numbers inside the grid as building heights. Numbers outside the grid indicate how many buildings can be seen from that direction, where a building blocks all buildings of lower or equal height behind it.

Edit: I should warn that the arithmetic here is pretty annoying.

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