ShmoopTube

Where Monty Python meets your 10th grade teacher.

Search Thousands of Shmoop Videos


Computer Science Videos 112 videos

AP Computer Science 1.2 GridWorld Case Study and APIs
493 Views

AP Computer Science 1.2 GridWorld Case Study and APIs. What is the direction of the actor?

AP Computer Science 1.4 Standard Algorithms
200 Views

AP Computer Science 1.4 Standard Algorithms. How many times will mystery be called for mystery(n) for n > 1?

AP Computer Science 2.3 Classes and Objects
191 Views

AP Computer Science 2.3 Classes and Objects. Which of the following is correct implementation of the Country class?

See All

AP Computer Science 3.1 Standard Algorithms 176 Views


Share It!


Description:

AP Computer Science 3.1 Standard Algorithms. What is the output of Recurse(3)?

Language:
English Language

Transcript

00:00

Sorry And here's your smoked use your brought to you

00:05

by rijker zhan brought to you by rekers jin Brought

00:09

to you by rekers asian brought to you by consider

00:14

the following code segment What is the output of re

00:17

curse three Ah we're thinking all right And here the

00:22

mental answers on numbers Okay this question Assessing what we

00:28

know about rikers in which is essentially having a method

00:31

call itself This creates a type of loop that goes

00:34

round and round around until some condition typically called the

00:37

base case is satisfied like a dog chasing its tail

00:40

in telling finally catches it a simple implementation of riker

00:43

shin might look something like this All right well this

00:47

method would take an imager And if it's greater than

00:50

zero print hello plus the imager Then it will decrease

00:54

the imager by one and call itself again And if

00:58

it's still greater than zero it'll do it again can

01:00

again and again it'll rikers decreasing over and over and

01:05

saying hello annie in inger goes up there until it

01:08

reaches zero go at zero it will simply return the

01:11

zero and the method will no longer call itself it's

01:15

a bit like the recursive algorithm shown in this question

01:17

except this one is also doing some funky math to

01:20

the imager so we'll need to carefully plot out what's

01:22

happening step by step here's our sniffing and the question

01:26

is asking pre output of re curse free All right

01:30

well starting at the top we're getting our method ready

01:32

with the parameter into end which will let us accept

01:35

that three and play with it as variable end when

01:38

rikers three gets called if it is less than one

01:42

will return the number one doesn't apply to us at

01:44

the moment though else will return one plus the product

01:48

of three times re curse and minus one better known

01:51

as to wait a min We're trying to calculate what

01:55

happens in rikers right now How can we use something

01:58

that hasn't been calculated yet Has a factor in our

02:01

calculation Shouldn't they shatter the universe somehow Well we're just

02:05

gonna have to dive into the first method again and

02:07

see how deep the rabbit hole goes at this point

02:09

Imager and is currently three and we're being asked for

02:12

re curse and minus one so it's just like calling

02:16

re cursed too We did The fancy man if end

02:20

now to remember is less than one return One else

02:24

return one plus three times rikers and minus one So

02:29

we'll be calling recruits again this time as reversed one

02:32

so it ends less than one return One else returned

02:35

one plus three times were cursed and minus one and

02:38

calling rikers yet again this time as rikers Zero Ah

02:42

but here we go If and is less than one

02:45

which it is We return one The product of rikers

02:48

zero is one We've stopped the lute e Now we

02:53

just have to climb back out of this home were

02:54

in back to rikers one We now know that riker

02:57

zero equals one So occurs one equals one plus the

03:01

product of three times one well in california three times

03:04

One two three and add one to that for four

03:07

So recruits one equals four and climbing up a rung

03:10

refers to it three times for his twelve plus one

03:14

is thirteen to rikers to is thirteen And at rikers

03:18

three three times thirteen is thirty nine plus one which

03:21

is forty So the product of rikers three is forty

03:24

Who A lot of work Someone really should write a 00:03:26.9 --> [endTime] computer program to handle it for us next time

Related Videos

AP Computer Science 1.2 GridWorld Case Study and APIs
493 Views

AP Computer Science 1.2 GridWorld Case Study and APIs. What is the direction of the actor?

AP Computer Science 1.4 Standard Algorithms
200 Views

AP Computer Science 1.4 Standard Algorithms. How many times will mystery be called for mystery(n) for n > 1?

AP Computer Science 2.3 Classes and Objects
191 Views

AP Computer Science 2.3 Classes and Objects. Which of the following is correct implementation of the Country class?

AP Computer Science 3.4 Inheritance, Abstraction, and Polymorphism
204 Views

AP Computer Science 3.4 Inheritance, Abstraction, and Polymorphism. Which of the following will satisfy the conditional if statement for boo, str,...

AP Computer Science 4.2 Standard Algorithms
191 Views

AP Computer Science 4.2 Standard Algorithms. What kind of algorithm is the following?