text stringlengths 1 81 | start float64 0 10.1k | duration float64 0 24.9 |
|---|---|---|
All right. | 4,042.151 | 0.499 |
So it doesn't look like all
that much progress, frankly. | 4,042.65 | 2.93 |
My left half of the list is now 4,
8, 2, 6, which is not really sorted. | 4,045.58 | 3.74 |
But we'll get there. | 4,049.32 | 1.21 |
What step comes next? | 4,050.53 | 1.55 |
I've just sorted the right half of
the left half of my original list. | 4,052.08 | 4.701 |
AUDIENCE: [INAUDIBLE]. | 4,056.781 | 2.409 |
SPEAKER 1: You're missing a step. | 4,059.19 | 1.47 |
AUDIENCE: [INAUDIBLE]. | 4,060.66 | 0.97 |
SPEAKER 1: Merge, that third step. | 4,061.63 | 1.98 |
Once you've sorted the
left half of something, | 4,063.61 | 2 |
then you've sorted the
right half of something. | 4,065.61 | 1.958 |
Now you have to merge them or
weave them together somehow. | 4,067.568 | 2.942 |
So the left half of the list in
the story at the moment is 4 and 8. | 4,070.51 | 3.25 |
The right half is 2 and 6. | 4,073.76 | 1.75 |
So here's where mentally
you can kind of bring out | 4,075.51 | 2.309 |
your fingers to think through this sort
of conceptually, or in pseudocode code. | 4,077.819 | 3.291 |
Here's the left list. | 4,081.11 | 1.69 |
Here's the right list,
or the right half. | 4,082.8 | 2.13 |
So how do I merge these two together? | 4,084.93 | 1.577 |
Well, it turns out--
and you can see it now. | 4,086.507 | 1.833 |
Before it was idiotic that we
just were merging lists of size 1. | 4,088.34 | 2.85 |
It's pretty easy. | 4,091.19 | 0.89 |
Here now, we have something
substantive to talk about. | 4,092.08 | 2.51 |
So I have one list here, one list here. | 4,094.59 | 2.33 |
Which element from these two
lists obviously comes first? | 4,096.92 | 4.67 |
So 2. | 4,101.59 | 1.11 |
And so what I'm going to do is then
2 is going to have to come down here. | 4,102.7 | 3.369 |
And then I can advance my
right hand so to speak. | 4,106.069 | 2.491 |
And now, compare 4 and 6. | 4,108.56 | 1.379 |
What's going to come next? | 4,109.939 | 1.641 |
4. | 4,111.58 | 0.72 |
Now I can advance my left hand. | 4,112.3 | 1.389 |
I compare 8 and 6. | 4,113.689 | 1.311 |
Which comes next? | 4,115 | 1.29 |
6. | 4,116.29 | 0.63 |
Now, my right hand, its job is done. | 4,116.92 | 1.93 |
I have only one more to do. | 4,118.85 | 2.31 |
And this. | 4,121.16 | 0.54 |
So what's key in the merging
is that you essentially | 4,121.7 | 2.6 |
have this left hand and
this right hand concept. | 4,124.3 | 2.49 |
Each of them kind of steps forward
over time, but you never go back. | 4,126.79 | 3.77 |
You never double back. | 4,130.56 | 1.29 |
So it's this sort of linear relationship
with your left and right hand | 4,131.85 | 2.968 |
as you're merging the lists together. | 4,134.818 | 1.541 |
So pictorially, let's see that. | 4,136.359 | 1.5 |
We compare 4 and 2. | 4,137.859 | 2.091 |
2 goes first. | 4,139.95 | 1.09 |
Then, 4. | 4,141.04 | 1.04 |
Then, 6. | 4,142.08 | 0.92 |
Then, 8. | 4,143 | 0.649 |
Where am I in the story? | 4,143.649 | 1.33 |
I mean, we've been droning
on for some time now. | 4,144.979 | 3.09 |
I have just successfully sorted what? | 4,148.069 | 3.511 |
The left half of the original
list, which means the next step is? | 4,151.58 | 3.568 |
AUDIENCE: Sort the right. | 4,155.148 | 1.041 |
SPEAKER 1: Sort the right
half of the original list. | 4,156.189 | 2.29 |
So I can box that in to
draw attention to it. | 4,158.479 | 2.181 |
How do I sort a list of size 4? | 4,160.66 | 1.52 |
Well, that's really
just 2 lists of size 2. | 4,162.18 | 2.13 |
Let's sort the left half. | 4,164.31 | 1.21 |
How do I sort a list of size 2? | 4,165.52 | 1.5 |
Well, that's really just a
list of-- 2 lists of size 1. | 4,167.02 | 4.28 |
Done. | 4,171.3 | 0.5 |
1 is sorted. | 4,171.8 | 0.929 |
Done. | 4,172.729 | 0.5 |
7 is sorted. | 4,173.229 | 0.851 |
Now I have to merge them together. | 4,174.08 | 1.48 |
1 comes first, then 7. | 4,175.56 | 3.009 |
OK, now sort the right half of the
right half of the original list. | 4,178.569 | 4.071 |
OK. | 4,182.64 | 0.85 |
Sort the left half. | 4,183.49 | 1 |
Done. | 4,184.49 | 0.55 |
Right half. | 4,185.04 | 0.6 |
Done. | 4,185.64 | 0.67 |
Merge them together
into some extra space. | 4,186.31 | 2.629 |
3, and then 5. | 4,188.939 | 2.271 |
Now where am I in the story? | 4,191.21 | 1.939 |
Now I have sorted the left
half of the original right half | 4,193.149 | 4.085 |
and the right half of
the original right half, | 4,197.234 | 1.916 |
so now I have to merge them together. | 4,199.15 | 2.81 |
So 1, 3, 5, 7. | 4,201.96 | 5.24 |
Almost there. | 4,207.2 | 0.94 |
Now we're sort of rewinding in time. | 4,208.14 | 1.94 |
Now we're at the very first
chapter in the story-- | 4,210.08 | 2.49 |
sort left half, sort right half, merge. | 4,212.57 | 2.37 |
I have that one final merge step. | 4,214.94 | 1.64 |
So what comes first from the
left half and the right half? | 4,216.58 | 3.96 |
1, 2-- even if you've
lost track of the story, | 4,220.54 | 3.43 |
the answer's going to be
1, 2, 3, 4, 5, 6, 7, 8. | 4,223.97 | 2 |
But 1, 2, 3. | 4,225.97 | 2.24 |
But notice what's
happening here in effect. | 4,228.21 | 1.97 |
Whatever code is implementing this,
it's as though my right and left | 4,230.18 | 3.67 |
fingers are just moving from left to
right, plucking off the element that | 4,233.85 | 4.72 |
is indeed then the smallest. | 4,238.57 | 3.61 |
That was a heck of a lot of work. | 4,242.18 | 1.42 |
And frankly, that story seemed to take
longer to tell than any of the others. | 4,243.6 | 5.64 |
But what happened? | 4,249.24 | 1.156 |
And in fact, I've left deliberately,
with this little animation | 4,250.396 | 2.624 |
of sorts, on the screen the
remnants of where we came. | 4,253.02 | 2.7 |
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