Name: CS50 2019--閱讀3--分類整理 (CS50 2019 - Lecture 3 - Sorting)
Uploaded: 2021-01-14T10:51:12.000Z
Duration: 5 min 4 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

情態助動詞 A2

if a few stress balls left and we could perhaps do this a little dramatically, Maybe with eight volunteers.

Okay, so one about 23 if we could Okay, four in the middle of their 567 And let's see and lets me come up here.

You do it after and have a hand in the middle.

And, Brian, if we could go ahead and equip our volunteers each with a number, we're gonna go ahead and see if we can't solve together the idea off finding an algorithm for sorting the numbers at hand.

So in just a moment, each of you will be handed a number.

In the meantime, let's go ahead and just say, a quick introduction, who you are, and perhaps your house cruise.

Apt Accord from Turkey for a foe ho from Detroit.

Alison Hollis, cause I'm first year from Cleveland Cloud.

I mean, Wigglesworth and I'm from Atlanta.

I'm your Well, I'm also from Wigglesworth.

Bonnie, aiming low line from Beijing in Ann Arbor.

And I'm noticing now is you might be too.

We have nine volunteers on stage, so we're gonna go ahead and solve this.

That's okay if you What's your name again?

You're gonna be maybe my assistant, if you could, as we sort these elements.

Let's go ahead and give you the mike here.

Each of you has been handed a number that happens to match with this, which is just so unsorted list of numbers.

And let me just ask that are eight volunteers here.

Okay, so let me ask any of you and will hand you the mike if need be.

What was the algorithm used to sort yourselves human intuition.

If, like the person who's left me like who is supposed to be larger than me is larger than me.

And if he was larger than me then I stayed there And if I was larger than him, I just switched places with him.

A sort of locally optimal approach where you just kind of look to the left and right and sort of fix any transposition, zor mismatches.

And in fact, let's go ahead and try and apply that same idea.

Can all eight of you, Reese, order yourselves just like that?

So that you're standing below your number so that we're undoing the human intuition that we just executed.

And now let's go ahead and say, All right.

So, bunny, if you don't mind helping direct us there to direct us here, we clearly have now an unsorted list of numbers.

Let's just bite off this problem one bit at a time.

So, for instance, YouTube your names again.

So what would be the locally optimal solution here?

They were switched Shorter's OK, Please do that.

All right, Now, let's consider six and eight.

I mean, I'd argue we are closer because right, like, eight somehow made its way all the way to the correct destination, even though we still have kind of a mess here to fix.

But notice that the solution got better in this direction and a little better this direction.

So if you would proceed from this order, uh, you two would switch five and 66 and to remain, and then the next person's seven and four horse, which I seven and one inch and then.

No, But look, the problem is getting better.

It's closer to solution, because now we have eight in place and seven in place.

So we've taken a bite out of the problem, if you would.

So if you want to tell everyone what to do perro eyes pretty quickly.

So everyone Human intuition, if you will.

Could everyone, if the person on your right is smaller than you, switch with them and then do that again.

So even though we allowed it to get a little organic there at the end Now, is the assorted Yes.