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.
