Solved

copyEvens challenge

Posted on 2016-08-30
6
105 Views
Last Modified: 2016-09-01
I am working on below challenge
http://codingbat.com/prob/p134174

Psedo code:
0. create new array of given count
1. for given arry loop through it
2. check if each element is even or not
3. if even fill till the new array ends
4. return new array
I wrote my code as below

public int[] copyEvens(int[] nums, int count) {
  int[] arr=new int[count];
  for(int i=0;i<nums.length-1;i++){
    if(nums[i]%2==0){
      arr[i]=nums[i];
      
      
    }
  }
  return arr;
}

Open in new window






I am not passing all tests
xpected      Run            
copyEvens([3, 2, 4, 5, 8], 2) → [2, 4]      Exception:java.lang.ArrayIndexOutOfBoundsException: 2 (line number:5)      X      
copyEvens([3, 2, 4, 5, 8], 3) → [2, 4, 8]      [0, 2, 4]      X      
copyEvens([6, 1, 2, 4, 5, 8], 3) → [6, 2, 4]      Exception:java.lang.ArrayIndexOutOfBoundsException: 3 (line number:5)      X      
copyEvens([6, 1, 2, 4, 5, 8], 4) → [6, 2, 4, 8]      [6, 0, 2, 4]      X      
copyEvens([3, 1, 4, 1, 5], 1) → [4]      Exception:java.lang.ArrayIndexOutOfBoundsException: 2 (line number:5)      X      
copyEvens([2], 1) → [2]      [0]      X      
copyEvens([6, 2, 4, 8], 2) → [6, 2]      Exception:java.lang.ArrayIndexOutOfBoundsException: 2 (line number:5)      X      
copyEvens([6, 2, 4, 8], 3) → [6, 2, 4]      [6, 2, 4]      OK      
copyEvens([6, 2, 4, 8], 4) → [6, 2, 4, 8]      [6, 2, 4, 0]      X      
copyEvens([1, 8, 4], 1) → [8]      Exception:java.lang.ArrayIndexOutOfBoundsException: 1 (line number:5)      X      
copyEvens([1, 8, 4], 2) → [8, 4]      [0, 8]      X      
copyEvens([2, 8, 4], 2) → [2, 8]      [2, 8]      OK      
other tests
X      
Your progress graph for this problem

How to improve/modify my design, code and any other alternate approaches. please advise
0
Comment
Question by:gudii9
  • 4
6 Comments
 
LVL 9

Expert Comment

by:Subrat (C++ windows/Linux)
ID: 41777457
In for loop it should be
I < nums.length

And other observation is,  you are passing no of even elements are 2 but in actuality trying to access 3. So getting array out of bound exception
0
 
LVL 9

Expert Comment

by:Subrat (C++ windows/Linux)
ID: 41777460
int temp =0;

for(int i=0;i<nums.length;i++){
      if(nums[i]%2==0 &&  temp < count){
          arr[temp++]=nums[i];
      }
}

But this code can be improved.
0
 
LVL 9

Expert Comment

by:Subrat (C++ windows/Linux)
ID: 41777468
public int[] copyEvens(int[] nums, int count) {
  int[] arr=new int[count];
  int temp = 0;
  for(int i=0; i<nums.length; i++){
    if(nums[i]%2==0 &&  temp < count){ 
          arr[temp++]=nums[i]; 
    }
  }
  return arr;
}

Open in new window

0
The New “Normal” in Modern Enterprise Operations

DevOps for the modern enterprise offers many benefits — increased agility, productivity, and more, but digital transformation isn’t easy, especially if you’re not addressing the right issues. Register for the webinar to dive into the “new normal” for enterprise modern ops.

 
LVL 9

Accepted Solution

by:
Subrat (C++ windows/Linux) earned 500 total points
ID: 41777470
Better would be instead of iterating all elements of array, loop only upto your count is reached and exit from loop.

Ex:
public int[] copyEvens(int[] nums, int count) {
  int[] arr=new int[count];
  int temp = 0;
  for(int i=0; (temp < count) && (i < nums.length); ++i){
    if(nums[i]%2==0){ 
          arr[temp++]=nums[i]; 
    }
  }
  return arr;
}

Open in new window

0
 
LVL 3

Expert Comment

by:Donna
ID: 41777472
FYI ... gudii9 has posted about 20 challenges from codingbat.com site...just to watch you guys jump through hoops. Is that what EE does? If it is, I for one, am leaving...
0
 
LVL 7

Author Comment

by:gudii9
ID: 41780956
public int[] copyEvens(int[] nums, int count) {
  int[] arr=new int[count];
  int temp = 0;
  for(int i=0;(temp<count)&&(i<nums.length);i++){
    if(nums[i]%2==0){
      arr[temp++]=nums[i];
      
      
    }
  }
  return arr;
}

Open in new window


i like temp approach. Above (with i++ instead of ++i) also passed all tests. Any difference using i++ or ++i in this challenge?
0

Featured Post

Master Your Team's Linux and Cloud Stack!

The average business loses $13.5M per year to ineffective training (per 1,000 employees). Keep ahead of the competition and combine in-person quality with online cost and flexibility by training with Linux Academy.

Question has a verified solution.

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

Suggested Solutions

This is an explanation of a simple data model to help parse a JSON feed
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.
The viewer will be introduced to the technique of using vectors in C++. The video will cover how to define a vector, store values in the vector and retrieve data from the values stored in the vector.
In this fifth video of the Xpdf series, we discuss and demonstrate the PDFdetach utility, which is able to list and, more importantly, extract attachments that are embedded in PDF files. It does this via a command line interface, making it suitable …

828 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