Leetcode 803. Bricks Falling When Hit

Given an m×n grid where a brick is stable if connected to the top (directly or via neighboring bricks), apply a sequence of hits that remove bricks and return how many additional bricks fall after each hit. The algorithmic challenge is to compute these results efficiently for up to 200×200 grids and many hits by reasoning in reverse and tracking connectivity (e.g., with Union-Find) to the top.