that also means, that if the clue number is 1, numbers are in descending order from clue side

Was hard to understand, but as did, (for your example) looking from the bottom you see buildings 2, 3, 4 (doesn't see the building 1, because building 3 blocks it). So you see 3 buildings in this column from bottom, that's why the clue is 3

When exactly are skyscrapers blocked by taller ones behind them? Because the 3rd column in the solution to the example, it says that from the bottom, three are visible, but a skyscraper of height 3 obviously blocks a skyscraper of height 1. There isn't even a possible permutation, while looking at only one column or row, where the hints on the sides are 1 and 3 with my understanding. I'm clearly illiterate or something so someone please explain

This is THE way of solving this, thanks for sharing

This isn't meant to be practical, I just wanted to see if I could have a single loop instead of 4 seperate ones for each direction. The incDir() offsets in the main loop, and after the 2nd loop, are the filthiest thing I think I've coded (apart from putting a ton of things here on one line unnecessarily, and the bitwise & instead of modulus for powers of two). I think it's beautifully disgusting implementation, with a bit of an obfuscation kinda thing going on

log10 has issues with large numbers close to having another digit (like 9999999999999999) and will return the incorrect value (causing counted digits to be 1 greater than what it has) due to rounding errors. These are relatively rare edge cases in most datasets but something to keep in mind