Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

bunnyEars challenge

Posted on 2016-09-09
6
Medium Priority
?
250 Views
Last Modified: 2016-09-13
Hi,

I am working on below challenge
http://codingbat.com/prob/p183649


We have a number of bunnies and each bunny has two big floppy ears. We want to compute the total number of ears across all the bunnies recursively (without loops or multiplication).

bunnyEars(0) → 0
bunnyEars(1) → 2
bunnyEars(2) → 4
I am not clear on above desription. what it mean by computing recursively?
 please advise
0
Comment
Question by:gudii9
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
6 Comments
 
LVL 14

Assisted Solution

by:CPColin
CPColin earned 500 total points
ID: 41791988
A "recursive method" is one that calls itself in order to compute a value. Explaining much more about the concept would pretty much solve the challenge for you. You have a better start going in one of the other questions you just posted.
0
 
LVL 7

Author Comment

by:gudii9
ID: 41792180
The idea of calling one function from another immediately suggests the possibility of a function calling itself. The function-call mechanism in Java supports this possibility, which is known as recursion.
Your first recursive program. The "Hello, World" for recursion is the factorial function, which is defined for positive integers n by the equation
n!=n×(n−1)×(n−2)×…×2×1
n!=n×(n−1)×(n−2)×…×2×1
The quantity n! is easy to compute with a for loop, but an even easier method in Factorial.java is to use the following recursive function:
public static long factorial(int n) {
    if (n == 1) return 1;
    return n * factorial(n-1);
}
We can trace this computation in precisely the same way that we trace any sequence of function calls.
factorial(5)
   factorial(4)
      factorial(3)
         factorial(2)
            factorial(1)
               return 1
            return 2*1 = 2
         return 3*2 = 6
      return 4*6 = 24
   return 5*24 = 120

i am reading from below link
http://introcs.cs.princeton.edu/java/23recursion/
0
 
LVL 37

Assisted Solution

by:zzynx
zzynx earned 500 total points
ID: 41793821
So in fact you're asking what recursion is. I would use Google for that.
Eg.
Explanation of recursion
An introduction to recursion
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 32

Accepted Solution

by:
awking00 earned 1000 total points
ID: 41794832
Maybe a general description of what this challenge is doing will offer a better understanding of recursion. We know that if there are no bunnies, there will be no ears (the base case). We can also agree that if there is one bunny, it will have two ears. But if you look a little deeper for the case of 1 bunny, you can see that it is equivalent to 2 plus the bunnyEars(0) function call which is equivalent to 2 + bunnyEars(bunnies - 1). If bunnies equal 2, that's equivalent to 2 + bunnyEars(1). If we keep making calls to the bunnyEars function passing in the bunnies value - 1 and adding 2, we eventually will reach the point where bunnies = 0 (i.e. the base case) and the function will "recursively" return the number of ears dictated by the value of bunnies. Hope this helps a little bit.
0
 
LVL 7

Author Comment

by:gudii9
ID: 41796790
pseudeo code:
1. if o bunnies return ears 0;
2. if one bunny ears 0 i.e 2+bunnyEars(1-1)
3. if n bunnies 2+bunneyEars(n-1)
0
 
LVL 7

Author Comment

by:gudii9
ID: 41796795
public int bunnyEars(int bunnies) {
 if(bunnies==0){
   return 0;
 }
 else{
   return 2+bunnyEars(bunnies-1);
 }
}

Open in new window


i passed all the tests. any improvements or alternate approach?
0

Featured Post

Moving data to the cloud? Find out if you’re ready

Before moving to the cloud, it is important to carefully define your db needs, plan for the migration & understand prod. environment. This wp explains how to define what you need from a cloud provider, plan for the migration & what putting a cloud solution into practice entails.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

International Data Corporation (IDC) prognosticates that before the current the year gets over disbursing on IT framework products to be sent in cloud environs will be $37.1B.
Although it can be difficult to imagine, someday your child will have a career of his or her own. He or she will likely start a family, buy a home and start having their own children. So, while being a kid is still extremely important, it’s also …
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…
In this seventh video of the Xpdf series, we discuss and demonstrate the PDFfonts utility, which lists all the fonts used in a PDF file. It does this via a command line interface, making it suitable for use in programs, scripts, batch files — any pl…

715 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question