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AP Computer Science 3.5 Standard Algorithms 1 Views
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Description:
AP Computer Science 3.5 Standard Algorithms. What does the list look like after three passes?
Transcript
- 00:04
and here's your shmoop du jour now it's delicious nougat
- 00:06
filling all right the program is in build implement selection sort this [Question appears]
- 00:11
program like many other sorting programs will sort things are this particular
- 00:16
program is sorting candy which seems like a fun job in the grand scheme of
- 00:20
sort ology the program sorts by the ASCII value of the first letter of the
Full Transcript
- 00:26
brand name from highest to lowest candy names are case sensitive so what
- 00:31
does the list look like after three passes
- 00:34
all right near your potential answers
- 00:40
okay looks like we're being asked to take the first three passes in
- 00:44
the process of organizing the names of these candies in reverse order according [Candy bars appear]
- 00:49
to the ASCII standard our DS in the bottom of this we'll need a quick
- 00:52
refresher on the selection sort and we'll need to know a little bit about
- 00:56
ASCII and how to determine what should come first
- 00:59
well actually let's rewind it even a little more for a moment and go back to [Video rewinds on screen]
- 01:03
binary all information is ultimately stored and transmitted in binary text
- 01:09
you read image you see videos you watch all of it deep down judge the flood of [Man watching videos on computer]
- 01:14
1-0 the smallest amount of information is a bit a single one or a zero strap
- 01:21
eight of these bits together and you've got a bike assign a different value to
- 01:25
each bit in powers to do and you can use those eight bits to represent any value
- 01:30
from zero to 255 pretty clever all right and of course combined way
- 01:36
more bytes together and you can represent much more complex data
- 01:39
pictures of Grandma videos of sneezing pandas units [Person looking at picture of Grandma]
- 01:43
all right that's beside the point ASCII device was a standard way to
- 01:47
transmit by different values and have them mean the same thing through the [ASCII device linked to computers]
- 01:50
computer on the other side the agreed-upon solution starts with a
- 01:54
handful of control codes many of which aren't used in quarters and then divides [Control codes jump into pool]
- 01:58
into numbers capital letters and lowercase letters and there's a tional
- 02:02
punctuation cycle throughout so if anyone were to transmit this byte which
- 02:06
holds the decimal value 74 it should represent
- 02:11
a capital J practically any computer or device that could receive it well no impossible
- 02:16
this is all relevant to the question it says that we'll be sorting the candies [Boy sounds a horn to girl in classroom]
- 02:20
by ASCII values from highest to lowest and how we're sorting is another thing
- 02:26
selection sort is probably the simplest search algorithm to implement it's not
- 02:30
great for big job but for a handful of candy bars it'll be just fine [Man working on a car engine]
- 02:34
all it really does is travel down a list finding the lowest value or in our case [People with numbered t-shirts appear on field]
- 02:38
we'll be looking for the highest value and moving that to the front of the list
- 02:43
by swapping it with whatever was already there then it goes again starting from [People re-arrange order]
- 02:47
the next position and again and so on until the entire array has been sorted
- 02:51
okay that said we'll be traversing this list of candy looking for the highest
- 02:56
value ASCII character and according to the shark it'll probably be a lowercase
- 03:00
letter while on the first pass M&M is the highest value ASCII character and
- 03:05
we'll get moved to the head of the line switching places with KitKat next back [M&M switches with KitKat bar]
- 03:09
the highest value would be that capital T belonging to Twix which will switch
- 03:14
with Snickers and on our third path skittles will be higher value than the [Skittles value shown on chart]
- 03:19
others including Snickers ster they both begin with an uppercase s but that means
- 03:24
the next character would decide it and that lowercase K would be higher value
- 03:29
on the after chart then an uppercase int alright well after three passes our list
- 03:34
now looks suspiciously like option B which would be correct [Option B circled]
- 03:37
and now if anyone wants to ask you a question you can say hey I know that pun
- 03:42
and it stinks [Girl giving thumbs down at boys joke]
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