study(0122): faster runtimes [buy/sell stock II]

[massivebird]

Challenge

My current 0122 solution (natty) beats 91.89% in memory, but the runtime is incredibly slow. I'm not beating anyone in speed.

I like my solution! I derived it from a working dynamic programming approach that failed the memory constraints. I flattened the $nxn$ matrix into an $n$-length array. Super duper cool 🦖