Thanks for pointing out. I was wrong because I assumed that numbers would be in continuous increasing order when numbers in each row are written in a line taking each row at a time.
On Mon, Sep 27, 2010 at 5:49 PM, Nikhil Jindal <[email protected]>wrote: > @saurabh.nsit: > > Consider the following array: > > 1 2 6 7 > 2 3 7 8 > 4 5 8 9 > 5 7 9 10 > > And the item to be searched is 6. As I understand it, using your approach > you will search 6 in only the second and third row, which will not give the > correct solution. > Hope this clears a few doubts. > > @Gene: > Analysing the complexity of ur algo: > > T(n) = 3*T(n/2) + O(1) > > which is n^(log_2(3)) = n^1.6. > > Cheers > Nikhil Jindal > > On Sun, Sep 26, 2010 at 11:14 PM, saurabh singh <[email protected]>wrote: > >> As you mentioned ultimately element to be searched should either be in row >> 'i' (ahead of [i,i] element) or in row i+1 (before [i+1,i+1] element). Since >> each row contain numbers in sorted order so u can do binary search on these >> two rows and ultimately the complexity will be O(logn) only >> >> On Sun, Sep 26, 2010 at 7:34 PM, Nikhil Jindal >> <[email protected]>wrote: >> >>> >>> >>> On Tue, Sep 21, 2010 at 6:05 PM, saurabh singh >>> <[email protected]>wrote: >>> >>>> solution 1: >>>> use concept of quad-tree and do binary search in that tree >>>> >>>> solution 2: >>>> do binary search on major diagonal. ultimately u will narrow down to >>>> search for element in 2 rows. in these two rows again do binary search. >>>> >>> >>> How do you narrow down to two rows? Please explain. >>> By searching on the diagonal, you get two elements such that one is >>> lesser than the number being searched for and the next is greater. let them >>> be i,i, and i+1,i+1. >>> >>> So you remove the array from 0,0 to i,i and from i+1,i+1 to n-1,n-1. But >>> the number could be anywhere in the rest of the array >>> >>> >>>> >>>> any solution will lead you to O(log(n)) time >>>> >>>> >>>> On Tue, Sep 21, 2010 at 5:10 PM, jagadish <[email protected]>wrote: >>>> >>>>> Hi all, >>>>> Given a 2d array which is sorted row wise and column wise as well, >>>>> find a specific element in it in LESS THAN O(n). >>>>> PS: an O(n) solution would involve skipping a column or a row each >>>>> time from the search and moving accordingly. >>>>> Solution less than O(n) is desirable! >>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Algorithm Geeks" group. >>>>> To post to this group, send email to [email protected]. >>>>> To unsubscribe from this group, send email to >>>>> [email protected]<algogeeks%[email protected]> >>>>> . >>>>> For more options, visit this group at >>>>> http://groups.google.com/group/algogeeks?hl=en. >>>>> >>>>> >>>> >>>> >>>> -- >>>> Thanks & Regards, >>>> Saurabh >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Algorithm Geeks" group. >>>> To post to this group, send email to [email protected]. >>>> To unsubscribe from this group, send email to >>>> [email protected]<algogeeks%[email protected]> >>>> . >>>> For more options, visit this group at >>>> http://groups.google.com/group/algogeeks?hl=en. >>>> >>> >>> Please access the attached hyperlink for an important electronic >>> communications disclaimer: >>> http://dce.edu/web/Sections/Standalone/Email_Disclaimer.php >>> >>> >>> >>> -- >>> >>> >>> You received this message because you are subscribed to the Google Groups >>> "Algorithm Geeks" group. >>> >>> To post to this group, send email to [email protected]. >>> >>> To unsubscribe from this group, send email to >>> [email protected] >>> <algogeeks%[email protected]>. >>> >>> >>> For more options, visit this group at >>> http://groups.google.com/group/algogeeks?hl=en. >>> >>> >>> >> >> >> -- >> Thanks & Regards, >> Saurabh >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Algorithm Geeks" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]<algogeeks%[email protected]> >> . >> For more options, visit this group at >> http://groups.google.com/group/algogeeks?hl=en. >> > > Please access the attached hyperlink for an important electronic > communications disclaimer: > http://dce.edu/web/Sections/Standalone/Email_Disclaimer.php > > > > -- > > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > [email protected] > <algogeeks%[email protected]>. > > > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > > > -- Thanks & Regards, Saurabh -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
