Leetcode 790. Domino and Tromino Tiling

Count the number of ways to tile a 2×n board using 2×1 dominoes and L-shaped trominoes (rotations allowed), returning the result modulo 10^9+7. The core challenge is handling tromino-induced partial-column configurations, typically solved with dynamic programming over column states (full/partial) for n up to 1000.