@ anand kindly elaborate a bit On Mon, Jul 5, 2010 at 10:09 PM, Anand <anandut2...@gmail.com> wrote:
> Use a Heap of n-way merging: O(klogn) > > > On Sun, Jul 4, 2010 at 5:07 AM, Raajay <raaja...@gmail.com> wrote: > >> According to the problem there should be 'n * k' elements in all (on an >> average). For merging all the elements into a single list one has to look at >> all the elements at least once. (For eg in case of merging two lists of size >> n1 and n2, the worst case complexity in O(n1 + n2)). >> >> Extending to the multiple lists the complexity should be O(n k) atleast. >> >> We can merge two lists at a time. Say list1 and list 2 , list 3 and list 4 >> and so on... After this operation we will have (n/2) lists with 2k elements >> each. The time complexity of this set of merges in = (n/2) * (k + k) >> = nk. >> >> >> Now in the second pass (merging the resulting 2k length lists pairwise), >> we will have time complexity of (n/4) * (2k + 2k) = nk. Proceeding like >> this we will have , log n sets (passes) of merges. So complexity is O(nk log >> n). >> >> I have a gut feel that this should be the best we can do. Because if k = >> 1, we essentially have n single element lists. Merging them into one single >> list is equal to sorting them. For which the lower bound in n log n. >> >> On Sat, Jul 3, 2010 at 11:06, divya <sweetdivya....@gmail.com> wrote: >> >>> How do you merge n sorted lists with average length K in O(n*log(K)) >>> time? >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "Algorithm Geeks" group. >>> To post to this group, send email to algoge...@googlegroups.com. >>> To unsubscribe from this group, send email to >>> algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> >>> . >>> For more options, visit this group at >>> http://groups.google.com/group/algogeeks?hl=en. >>> >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "Algorithm Geeks" group. >> To post to this group, send email to algoge...@googlegroups.com. >> To unsubscribe from this group, send email to >> algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> >> . >> For more options, visit this group at >> http://groups.google.com/group/algogeeks?hl=en. >> > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to algoge...@googlegroups.com. > To unsubscribe from this group, send email to > algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- With Regards, Jalaj Jaiswal +919026283397 B.TECH IT IIIT ALLAHABAD -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algoge...@googlegroups.com. To unsubscribe from this group, send email to algogeeks+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
