Valid Sudoku - Amazon Interview Question - Leetcode 36 - Python

0:00 - Read the problem
4:49 - Drawing Explanation
8:50 - Coding Explanation

leetcode 36

#valid #sudoku #python
Disclosure: Some of the links above may be affiliate links, from which I may earn a small commission.

[ashtag]

Bro I'm literally in awe when you used simple division of indices with 3 to point to a particular square. Amazing as always.

[Hys-]

this is the first medium problem that ive done myself which aligns exactly with the optimal solution, i feel accomplished 😅

[jesuscruz]

the row/3 and colum/3 idea is sooo neat i love it. I was having trouble iterating thru each of the squares. Im doing the NeetCode 150 on your website and I love that you have videos for each of the problems even if i get the right solution i look at your videos to see the alternative ways to solve it.

[mehdiezatabadi]

This guy is more than just a legend :) He is THE legend!

[parthvalani]

I haven't seen that much easy explanation of all the code you explained. It helps me to improve my overall logical skills. Thanks Bud!!

[MP-nyep]

This is the best channel in the whole of YouTube🔥

[AkshithaKukudala]

What an explanation. I literally spend an entire day trying this problem and you explained me clearly within these few minutes. You are the best <3

[choiiohc]

I never thought in this question that tuple (r//3, c//3) could be keys for defaultdict. Amazing!

[sayaksengupta]

This solution is simply beautiful. You have my respect, Neetcode. <3

[akagamishanks]

I'm here to say it NeetCode is all time top 1 teacher when it comes to explaining and solving algorithm and data structure problems. My guy is HIM!!!

[reinventingdwheel]

the best way to do this really, i had been struggling with this problem for a few days now, the sudoku solver really, i did the more complex way at first but i was worried that i would not be able to think of that solution in a coding test but this way is beautiful

[gogolaygo]

Idk how i'd ever figure this one out without watching a video. As always, thanks!

[AlanWeiler-cr]

Dude, seriously, this solution was so elegant and brilliant. Thanks, for explaining these things so simply and effectively.

[hamzaehsankhan]

This makes my solution look like a crayon drawing of a 2-year-old. Awesome solution and well explained.

[dnguyendev]

The way you explain this problem is brilliant man! So glad I found your channel

[syafzal]

The implementation for the squares with floor division and using a tuple as the key is simply amazing!

[Myshio]

I did it exactly the same way but I opted for just using 1 hashmap where the key was the number and the value was a tuple of (row, column, box number), then at every value I can just look up if it exists in the hashmap and compare each value in the tuple. I can't tell which solution would be better in terms of time complexity though since I would have to iterate all 3 values of my tuple after the constant lookup.

[ramsesFPS]

Mind blown when you said you recorded on 4th of July!! It's been exactly one year! Thanks for everything you do

[_dion_]

this problem should have been in the hard category instead of medium. but u explained it really well as always. thanks.

[FionaTraiton]

I came to almost the same solution! Instead of using hash maps for the rows, columns, squares, I just initialized them as arrays of size 9 with a set at each position. Using defaultdict(set) is definitely a neat way to make the row, columns, squares sets.