[algogeeks] Re: selection problem.....

2008-04-22 Thread Pramod Negi
i didnt get what u want to so say (the bold lines) On 4/21/08, Dave [EMAIL PROTECTED] wrote: Use a divide-and-conquer algorithm to find the median, rearranging the array so that the values less than the median precede it in the array and the values greater than the median follow it. So the

[algogeeks] Re: selection problem.....

2008-04-22 Thread Varun S V
Hi Dave, Can you kindly eloborate your algorithm? How can we modify a single array in O(n) time, such that the median comes to become the n/2th element and smaller elements comes to the left side and larger elements comes to the right side? Kindly explain in detail. 2008/4/22 Pramod Negi [EMAIL

[algogeeks] Re: selection problem.....

2008-04-22 Thread Pramod Negi
make a partition about media as a pivot element On 4/22/08, Varun S V [EMAIL PROTECTED] wrote: Hi Dave, Can you kindly eloborate your algorithm? How can we modify a single array in O(n) time, such that the median comes to become the n/2th element and smaller elements comes to the left side

[algogeeks] Re: selection problem.....

2008-04-22 Thread Varun S V
Hi, Im a bit confused as how DAndC happens in O(n) time. Doesn't it take O(nlogn) time by the way the algo has been described above? we have to divide the array every time and again work on both the sub arrays. Can you kindly explain how does this take O(n) time? 2008/4/22 Pramod Negi [EMAIL

[algogeeks] Re: selection problem.....

2008-04-22 Thread Dave
The divide and conquer algorithm for finding the median is described in http://en.wikipedia.org/wiki/Selection_algorithm. Dave On Apr 22, 4:43 am, Varun S V [EMAIL PROTECTED] wrote: Hi Dave, Can you kindly eloborate your algorithm? How can we modify a single array in O(n) time, such that

[algogeeks] Re: selection problem.....

2008-04-22 Thread Dave
The divide and conquer algorithm for finding the median is described in http://en.wikipedia.org/wiki/Selection_algorithm. Dave On Apr 22, 6:02 am, Varun S V [EMAIL PROTECTED] wrote: Hi, Im a bit confused as how DAndC happens in O(n) time. Doesn't it take O(nlogn) time by the way the algo

[algogeeks] No fully polynomial approximation algorithm

2008-04-22 Thread Darth
Hi, I read a paper which claimed that for a particular problem called the multi-node service provisioning problem, a fully polynomial time approximation algorithm cannot exists unless P=NP. Does this also imply that we cannot create any algorithm that gives a solution say within (1+\epsilon) of