Valid Sudoku - Leetcode 36 - Hashmaps & Sets (Python)

The Python code for this problem can be found at my GitHub repo here: github.com/gahogg/Leetcode-So...
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[@nguyenkhiem2318]

Thanks Greg, you really have a natural talent for teaching. Was struggling with this one

[@saedf0]

Hey Greg, thanks for the content. Great solution, although i do wonder, how is it BIG O(1) when we have multiple loops? I'm not the best with the complexity identification.

[@GregHogg]

Thank you! And that's a great question (at any level). Technically, these loops are going to run a constant amount of times (not dependent on the size of the grid) because WE KNOW the grid will be a 9*9. To scan the grid, it takes exactly 81 positions. Not dependent on some N or something. So O(81) is just O(1) in big o talk. I hope this helps!

[@saedf0]

@@GregHogg ohhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh /*click moment*/ Man, I cant rely on explanations all the time, do you have any resources/ or easy tricks to remember this stuff. I've tried a few videos and identifying it kindve goes over my head I get that N^2 (for everytime we do this, run these steps) I also understand O(N), Do this Log N (Half each time, divide and conquer but when the code gets a little longer, kindve difficult to track but yh thanks for getting back :)

[@mercytum7045]

Thanks, Greg. This was really helpful!

[@GregHogg]

Glad it was helpful!

[@nathanaelcheramlak9332]

Helpful content, Keep going

[@GregHogg]

Thanks a ton 😊

[@HussainAli-hn2ef]

very helpful, thanks!

[@GregHogg]

Glad to hear it!!

[@arsheyajain7055]

Super helpful!!!!!

[@GregHogg]

Awesome 😎😎