##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
n ≤ 20 and tracking used elements
Use bitmask DP when you see these signals:
Small set size. is typical, since .
Subset tracking. You need to know which items have been used.
Order or assignment matters. TSP needs to track visited cities; assignment needs to track assigned tasks.
The state is or where represents the subset and might be the last element.
