Solved

triangle challenge

Posted on 2016-09-09
4
217 Views
Last Modified: 2016-09-11
Hi,

I am working on below challenge

http://codingbat.com/prob/p194781

Recursion-1 > triangle
prev  |  next  |  chance
We have triangle made of blocks. The topmost row has 1 block, the next row down has 2 blocks, the next row has 3 blocks, and so on. Compute recursively (no loops or multiplication) the total number of blocks in such a triangle with the given number of rows.

triangle(0) → 0
triangle(1) → 1
triangle(2) → 3

i have not understood above description.
what is row and what is block and how they are related to triange and what we have to return
Can you 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
  • 2
  • 2
4 Comments
 
LVL 27

Accepted Solution

by:
rrz earned 500 total points
ID: 41792161
what is row and what is block and how they are related to triange and what we have to return
They could have named this challenge "stairs". Here is a image I found to illustrate the concept. stairs It's shape is roughly a triangle. They want to give total number of blocks needed to construct the triangle(stairs).
0
 
LVL 7

Author Comment

by:gudii9
ID: 41792191
i understood now with above image.

public int triangle(int rows) {
  if(rows==1){
    return 1;
  }
  return rows+triangle(rows-1);
}

Open in new window

above fails one test case

xpected      Run            
triangle(0) → 0      Exception:java.lang.StackOverflowError (line number:2)      X      
triangle(1) → 1      1      OK      
triangle(2) → 3      3      OK      
triangle(3) → 6      6      OK      
triangle(4) → 10      10      OK      
triangle(5) → 15      15      OK      
triangle(6) → 21      21      OK      
triangle(7) → 28      28      OK      
other tests
how to decide base case begin with 0 or with 1. it is failing 0 case now
0
 
LVL 27

Expert Comment

by:rrz
ID: 41792194
how to decide base case begin with 0
Just do the same with base case with 0 instead of 1.
0
 
LVL 7

Author Comment

by:gudii9
ID: 41793645
with one failing one.

with 0 base case all passing

public int triangle(int rows) {
  if(rows==0){
    return 0;
  }
  return rows+triangle(rows-1);
}

Open in new window

0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Did you know SD-WANs can improve network connectivity? Check out this webinar to learn how an SD-WAN simplified, one-click tool can help you migrate and manage data in the cloud.

Question has a verified solution.

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

Computer science students often experience many of the same frustrations when going through their engineering courses. This article presents seven tips I found useful when completing a bachelors and masters degree in computing which I believe may he…
This article will inform Clients about common and important expectations from the freelancers (Experts) who are looking at your Gig.
Viewers will learn about arithmetic and Boolean expressions in Java and the logical operators used to create Boolean expressions. We will cover the symbols used for arithmetic expressions and define each logical operator and how to use them in Boole…
Introduction to Processes

691 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