You learned Bitmask DP for subset-based states.
A bitmask represents a subset as an integer. Bit set means element is included. This compresses exponential state spaces into manageable .
TSP (Traveling Salesman Problem)-style problems need : which cities visited, which city you're at. Assignment problems often need just .
SOS DP handles subset aggregation in . Process one bit at a time, building from smaller flexibility to full subset sums.
When and track subsets, think bitmask. The exponential state space is tractable for small .