Name: Python数独ソルバー - Computerphile (Python Sudoku Solver - Computerphile)
Uploaded: 2021-01-14T10:15:12.000Z
Duration: 10 min 53 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

this game called Sudoku, it's Ah puzzle, which you find no off in newspapers and other places.

to 不定詞

動名詞

Ss of programmer computer scientists You can you can have different fun in, like writing a program which sauce it.

I mean, that doesn't mean that obviously, was a program.

If you if you if you want, it's just enjoyable.

It was a puzzle, but also fun till I support you.

So we see this great, and there's some numbers fit in, and the goal is to fill in all the remaining numbers every in every square.

That should be number from 1 to 9, and the rules of the game is that you cannot use the same number twice, you know, on a column on one off the squares.

So, for example, if you look in this middle square here, you cannot put a run in because there's a woman.

If they hear four 555 is an order, actually, five would be possible.

There's a six year a seven here in eight here and nine here.

Hence, what do we do to be 55 and now we can continue this and obviously easier.

Sometimes you have to be a bit more clever.

And yet this is one of the examples for using our courts and our python book us, where we show the idea of what's called backtracking computer Science.

And actually it uses another to use a magic trick I've been talking about before.

And that means the magic trick is Kirsten.

I'm using Python here with a thing called Jupiter and I have pre cooked, but it's like the's chests and TV.

They do it like it's a little thoughts, which is too long to prepare their robbery.

Two and 1/2 Danza's First of all, I d find.

Which is exactly the same grit as we have seen as a list of lists to the manger.

They're very basically in python, and then, actually, if you print this, it looks very ugly.

Looks like this, and that's a very readable and that's probably because we want to use this to output the solution.

Now you know our call us we actually liked Ah, Delia.

We employed a library quote, lumpy, numb pie and this escort definition of the Matrix.

We can just use this matrix to print this grit in the baby can actually read it now.

It's a function which determines whether, on a certain position we can put the number so have got three perimeters by Ex N N.

So is to vie first and extent because it's the order in which T embassies appear to use this presentation.

It's a number, and it returns to if it's possible to put this number there, and Ford's otherwise and what it does is it.

Checks first go and then checks the column and then checks this career on the digits are not so important, especially checking this career.

It's a little bit, Yeah, Clyde's a little bit off cleverness, but that's okay.

We can, for example, ask It's a position in the middle of its chest, indexed for four, because we can't with the 01234 Is it possible to put a three on hopes, answers.

No, this is possible in the same position to put a five.

Meet us because we're just working on this global great.

Maybe let's tell Python it's global and what do we do?

My first of all, we have to find an empty position.

Which means we have to do is to loops for y in range nine.

That's Python for counting from 0 to 8, able to eight nine possibilities.

And now you check if there is a zero at this position.

And here I have to save eyes of the wife.

Now I would go through all the numbers I can put their, which are the numbers from 1 to 9.

So four and in and I have to say range one comma, 10 That's always a bit funny because it comes from one tonight.

Just it counts to run before it's like if you do, loop was in less than it doesn't get to that in just that one more.

Okay, so now we have to check, if possible, in position by Kama X comma.

So that's a good call for Rikers in Just called the same function idea.

So now, Because so often, the tie to find the next and the next and the next empty square part of kennels have happened that our choices are not really good.

We get into debt, we cannot feel the letter off the great in this case, we return.

We take this number off, we make it blink again.

This is actually accept what's called back taking you try And if it turns out we cannot complete the solution.

If you have tried all possibilities for for empty square and none of them worked, that means via in a dead end.

But you have to Quito you go back to ever called us.

Now let's see, we have gone through the school.

We have looked at all the fields and we end up here.

Now the question is, how could we end up here?

Because whenever we find position and we go through all the numbers we return So the only way we can add up here is if there wasn't an empty space.

Well, which for you finished and we're finished.

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Python数独ソルバー - Computerphile (Python Sudoku Solver - Computerphile)

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