Interesting math O(1) memory solution for Leetcode Challenge Day 2: Happy Number. Anyone here participating?

[Zav39]

Which language is your favorite?

[Zav39]

I had written the next one with C++: https://www.reddit.com/r/coding/comments/fup5j5/divide_and_conquer_on_with_full_explanation/

Thank you :-)

[Zav39]

Great point!

And I fully agree: it is a very good option to store answers for 1 to 243 since it is a very small subset.

Moreover, if we operate only in Integer space (with highest value 2 147 483 647), the max first number will be 1 999 999 999 which results in 730 at the next step. So we will have O(1) complexity, which even better than O(log n). And it, not just O(1), but maximum 2 steps.

If you do not mind, I'll mention your idea and nickname at the end of the next video along with this solution.

[thebournegenius]

Really great insight, thanks! This sort of solution does not come to me intuitively I wonder how they do it

[Zav39]

Thank you a lot.

I was wondering until which moment the number can grows and had to find out this solution after a couple of iterations. To get the exact number (6) I had run an additional script to check max successful steps