Solved

triangle challenge

Posted on 2016-09-09
4
194 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

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

Suggested Solutions

Whether you’re a college noob or a soon-to-be pro, these tips are sure to help you in your journey to becoming a programming ninja and stand out from the crowd.
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 tutorial covers a step-by-step guide to install VisualVM launcher in eclipse.
This theoretical tutorial explains exceptions, reasons for exceptions, different categories of exception and exception hierarchy.

733 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