@sanjiv : if x is the majority element then it is ok, but if not(x is present and not majority element), u'r method doesn't work ..
On Sun, Apr 1, 2012 at 9:38 PM, rahul sharma <[email protected]>wrote: > http://www.geeksforgeeks.org/archives/503 > > > On Sun, Apr 1, 2012 at 6:54 PM, sanjiv yadav <[email protected]>wrote: > >> if all values x are known to be contiguous then I think it will take o(1) >> time because it will be majority element if it occurs more than n/2 times >> as x must be at the middle. >> >> so if mid=(low+high)/2 and x==a[mid]then x is majority element otherwise >> not. >> >> just check....let me know. >> >> On Thu, Feb 9, 2012 at 11:40 PM, Don <[email protected]> wrote: >> >>> It can't be done in O(log n) unless the array is sorted or there is >>> some other special property, for example, if all values x are known to >>> be contiguous, allowing you to use a binary search to find the first >>> and last location of x. >>> >>> In the general case it is impossible in O(log n) because you have to >>> examine at least n/2 elements to reach a conclusion. In some cases you >>> must examine all n elements. >>> >>> Don >>> >>> On Feb 8, 1:45 pm, Prakhar Jain <[email protected]> wrote: >>> > Hello everyone, >>> > >>> > suppose we have an array of size n and a number, say x, and we have to >>> > determine whether the number x is present in the array more then n/2 >>> times >>> > or not....? >>> > can we have an O(log n) algo for determining it......?..pls help...!!! >>> > >>> > -- >>> > -- >>> > Prakhar Jain >>> > IIIT Allahabad >>> > B.Tech IT 3rd Year >>> > Mob no: +91 9454992196 >>> > E-mail: [email protected] >>> > [email protected] >>> >>> -- >>> 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. >>> >>> >> >> >> -- >> Regards.... >> >> Sanjiv Yadav >> >> MobNo.- 8050142693 >> >> Email Id- [email protected] >> >> -- >> 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. >> > > -- > 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. > -- 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.
