Same is as if blank isn't true, except no value is valid too. Saying more would probably spoil the kata, but you might be overthinking it.

the language here is ambiguous, but it is assumed that we are talking about an entire window, hence if it goes above the window it will go down for a second viewing.

That can happen if your algorithm isn't efficient. Any method that relies on finding the depth of each pixel separately will likely be too slow on the large images.

its a library function https://man7.org/linux/man-pages/man3/toupper.3.html

Tests are fine (but they don't give the input when a test fails). What is happening actually is that the tests stop as soon as your code returns a bad answer. Your code fails on one fixed test, and in random tests. you should try to print the input using printf.

🤣🤣

tbh, if you check for what the conditions the instructions give properly, you can eliminate any cases that would cause problems. The rest is just figuring out implementation (Double Declining Balance Depreciation) or just recursion both worked for me

please read this paragraph: https://docs.codewars.com/training/troubleshooting/#timeout

Mostly because my parents seperated when I was younger.