[algogeeks] Re: Finding elements near the median

2011-01-27 Thread Dave
As described earlier, it can be done in O(n) independently of k. 1. Find the median, M: O(n) 2. Form a second array containing y(i) = abs(x(i) - M): O(n) 3. Find the kth smallest element of this array, K: O(n) 4. Scan the original array and locate the first k elements such that abs(x(i) - M) <= K:

[algogeeks] Re: Finding elements near the median

2011-01-27 Thread Jammy
I agree time should be O(kn) On Jan 26, 9:55 pm, Sharath Channahalli wrote: > a) Find the median - O(n) > b) remove the element and again find the median > c) conitnue b until you get k-1 elements > > time complexity - kO(n) > > On Wed, Jan 26, 2011 at 9:55 PM, ritu wrote: > > > solution is nice

Re: [algogeeks] Re: Finding elements near the median

2011-01-26 Thread Sharath Channahalli
a) Find the median - O(n) b) remove the element and again find the median c) conitnue b until you get k-1 elements time complexity - kO(n) On Wed, Jan 26, 2011 at 9:55 PM, ritu wrote: > > solution is nice!!but How to keep track of k closet numbers? > > > On Jan 23, 9:22 pm, ritesh wrote: > > 1

[algogeeks] Re: Finding elements near the median

2011-01-26 Thread ritu
solution is nice!!but How to keep track of k closet numbers? On Jan 23, 9:22 pm, ritesh wrote: > 1.) find x= median in o(n) > 2.) subtract x from each number of the array > 3.) find the k smallest number using o(n) algrithm > > On Jan 21, 4:04 am, snehal jain wrote: > > > Given an unsorted arr

[algogeeks] Re: Finding elements near the median

2011-01-23 Thread vivek_12315
using selection algorithm ... http://en.wikipedia.org/wiki/Selection_algorithm On Jan 24, 3:15 am, Anand wrote: > How to find K smallest using O(n) > > On Sun, Jan 23, 2011 at 9:33 AM, Dave wrote: > > @Ritesh: Very clever. In step 2 you should take the absolute value, > > meaning that you need a

Re: [algogeeks] Re: Finding elements near the median

2011-01-23 Thread Anand
How to find K smallest using O(n) On Sun, Jan 23, 2011 at 9:33 AM, Dave wrote: > @Ritesh: Very clever. In step 2 you should take the absolute value, > meaning that you need a copy of the original array in order to recover > the closest numbers, or in step 3 you should find the k smallest > absol

[algogeeks] Re: Finding elements near the median

2011-01-23 Thread Dave
@Ritesh: Very clever. In step 2 you should take the absolute value, meaning that you need a copy of the original array in order to recover the closest numbers, or in step 3 you should find the k smallest absolute values. It is more work, but still O(n), but then you don't need the extra copy of the

[algogeeks] Re: Finding elements near the median

2011-01-23 Thread ritesh
1.) find x= median in o(n) 2.) subtract x from each number of the array 3.) find the k smallest number using o(n) algrithm On Jan 21, 4:04 am, snehal jain wrote: > Given an unsorted array A of n distinct numbers and an integer k where > 1 <= k <= n, design an algorithm that finds the k numbers in