I solved Tetris a very similar way in high school. My approach was to treat it as a zero-sum, two player game. One player assigns pieces, and the other player p

I solved Tetris a very similar way in high school. My approach was to treat it as a zero-sum, two player game. One player assigns pieces, and the other player places pieces. Treating it this way allows using Minimax algorithm with any depth (similar to chess or other two player games!). The board evaluation function can penalize "caves" (empty orphaned spaces that have been covered by pieces above them). With a board evaluation function like this, alpha/beta pruning can be used. This gives great results!