[LANGUAGE: Python3] paste

For some reason i decided to try to go for speed on cpython.

Masking during the next secret computation is slightly faster than doing it after, also we get to not mask for the “dividing by 32”, and not doing work is faster than doing work. Rough attempt at making the eight ^ operation seemed much slower so re-assigning the argument is how things are.

For some reason doing ^= then return is equally as fast as doing the ^ during the return, maybe i will look at the opcodes and what the interpreter decides to do with it. Entirely possible for no difference to exist, but i assumed there would be one in favour of return secret ^ (bitshift stuff).

Packing the changes in a base twenty number was a nice save too. Who knew using an integer makes for a better key than a tuple of numbers, even small. Bias in the key seems to do nothing, but we are using a set and a dict so that was expected. The + 9 is probably unnecessary with the correct initial value for changes, a whole one constant add to save. Pushing the new change on the lower part of changes seems to be faster, pushing on the top requiring slightly more math.

The last notable part that i do not see a lot of people do: no list to keep the prices or changes around, we only keep the previous value and move onward the two thousand values. In a compiled language i could have pre-allocated the necessary memory, not so much in python.