Sign in to follow this  

Codility sample question

This topic is 2550 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I tried to post in the other two threads about it, but they're retired.
So long story, short. Why is this wrong? I didn't see the sample array they used to test the code so I had to go by was the sample array they had.

int equi ( int[] A ) {
long equiIndex = -1;
long equiTotal = 0;

if (A.Length == 0)
{
return (int)equiIndex;
}

if (A == null)
{
return (int)equiIndex;
}

foreach (int i in A)
{
equiTotal += i;
}

for (long j = 0; j < A.Length; ++j)
{
if (A[j] == - (equiTotal - A[j]))
{
equiIndex = j;
break; //even with this still wrong
}
}

return (int)equiIndex;
}




[Edited by - Alpha_ProgDes on December 25, 2010 9:54:54 AM]

Share this post


Link to post
Share on other sites
I can see a few problems offhand:

  • A.Length is accessed before checking if A is null (crash)

  • Cast from long to int may fail for very large arrays

  • The algorithm is wrong. Think carefully about what you're trying to do (find the equilibrium index, i.e. the sum of the first chunk of the array equals the sum of the remainder of the array) and compare this to what you're actually testing for.


This might be easier if you compare to the actual solutions provided in other languages here (even if you don't know Python, understanding the algorithm should be trivial).

Share this post


Link to post
Share on other sites

This topic is 2550 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this