ABC019C

https://gyazo.com/1aaceef3c8e29db0b95df8a27619e4ca

Thoughts.

Since x and 2x are identical, we can just divide by as much as we can divide by 2.

representative source of equivalence class

The number of times to break it is about 30 times, so there is plenty of time to spare.

Official Explanation

Oh, I see, I didn't explain enough about the determination of "whether or not the number has already been obtained".

So the number of numbers is about 10^5, but the range of values is 10^9, so you don't want to have an array with or without occurrences.

I didn't explain it, but I would put it in a Python set without thinking too much about it. This is a hash table, so O(1)

---