##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
(Trying all subsets)
An algorithm is O(2^n) if it explores all possible subsets or combinations. Recursive Fibonacci without memoization is exponential.
Each increment of n doubles runtime. This explodes fast. n = 30 might take seconds. n = 50 could take years.
Exponential algorithms are impractical for large inputs unless you can prune the search space.
