any further hints? I got rid of the division by modular inverse but still too slow for random test

thanks

just learned about the unfold method, seems useful

for the ones who don't wanna go into taylor series, search for the topic of round off value may help

I thought the test wouldn't use capital letter,have been baffled over empty.head error in scala for an hour.

the error grows larger with the test number since my solution always used the previous result(which is slight off) to calculate next one, is there a way to avoid this?(solved by using BigDecimal type in scala)

I got the same thing, it worked well in my local ide

cool, I didn't know rotationg clockwise 90 is just reversed transpose.
And also for that method I think you can reverse it before transpose, which should be more efficient.

nice tailrec, I did a similar thing but didn't make it tailrec and causes stack overflow

did't consider repeated smallist value