Create Sudoku Solver with Python in 20 minutes

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The goal of this tutorial is to explain step by step how a Sudoku solver is created with Python and what the logic behind each step is.

[bluegodofspeed]

Bro I've been wanting to do one of these projects to add to my resume, and I've watched a bunch of videos on the same topic. Yours is the clearest, most detailed, best video I've found. You explain every detail, take us step-by-step, is logical and not boring. Others type the same code but idk what they're saying. Thank you so much for your video. You explain perfectly // division to isolate the squares, you explain perfectly the column[i] to check row, column etc. It's perfect, thank you so much. You explain things very well.

[alitoto]

absolute legend if you are unsure to watch this video or another one then watch this one 100% best explanation ever

[reiherentenorbert]

Very elegantly solved! - I once wrote a solver myself, wrote much more code and did only find one solution. Excellent!

[josecarrera]

this is super intuitive, we are solving a sudoku program at uni and ours is so much more complicated

[MEEA]

That's the most clear explanation i have found ❤

[randyfriend]

Very nice explanation. It doesn't matter in this case, but as a FYI, // division does not round down. It truncates the remainders and only returns the integer part of the result. Knowing the difference would be important for a technical interview or a case where you were asked about Python knowledge/workings.

[parkuuu]

Recursion is so damn scary and brilliant at the same time. I can only hope to master this thinking style.

[rajat]

Bro, you explain this logic clearly thank you so much and keep growing

[raveenachakrapani]

What a precise and clear explanation !!! Thanks a ton !!

[goutvols]

I ran your code and added lots of print statements to understand where the code backtracks. It is the embedded solve() call which backtracks to the last known good row, column and then increments the counter by one (1).

[ChessQuickies]

Tysm!
This project was short and easy to understand and clear.
you just got an extra like!

[zerozeronine]

may use set difference to reduce some codes. eg {1, 2, 3, 4, 5, 6, 7, 8, 9} - set of numbers at that row - set of numbers at that column - set of numbers at that block = only possible numbers at that position. Some people even put those numbers in one byte to perform bitwise operations ^ &.

[paytakbaba]

bro thanks for helping for my project. apart all of that you helped me to understand

[clouddrive]

it was clear cut explanation, keep posting videos

[pranavkochhar]

very well explained. Thank you so much

[carlocirillo]

very good explaination. but i don't understand only one thing: how can writing "grid[row][column]" = 0 after solve() help if it doesn't find any solution?

[saransp]

Very good explanation ! Thank you. How we can give 'number' as user input and it will check with conditions ?

[ashishzarekar]

For me this code prints original(unsolved) grid only, Could someone help me please?

[williamgarrido]

lo mejor que eh visto .. saludos de colombia

[JoseMBrito-iuhg]

Very nice solution. I have two questions:
1) Where does the control go back to the previous cell when no number is possible for the current [row][column]?
2) How does it find other solutions? i don´t undestand how it does that after the input statement.