Efficient way to count occurrences of a key in a sorted array

Question

This was asked in on-site Microsoft interview.

Count the number of occurrences of a given key in an array.

I answered linear search because the elements may be s

Answer 1

Yes, you're right for unsorted array, but for sorted array you can use binary search to locate one occurence of the element and once that one occurence is found only scan adjacent elements until you find mismatches and then stop.