You have a board where candies fall due to gravity. Three or more consecutive candies of the same type (horizontally or vertically) are crushed and removed. Candies above fall down. Repeat until no more can be crushed.
Here's a simulation problem, but the order of crushing uses greedy logic: crush all possible matches at once, then apply gravity, and repeat. Constraint: the board can be up to , and you repeat until no matches exist. Each round reduces the total candy count, so the process terminates. The greedy aspect is crushing all matches simultaneously rather than one at a time.