Why this approach for finding last occurrence of an element failing for array inputs like: 1,2,3,4,2
Last Occurrence using binary search
This is a simple binary search algo and it works only on sorted arrays. Your input is not sorted. And this algo will only find the first occurrence it comes across. So use linear search towards the right when you find an element and if there is no element on the right, return the original element as the last occurence.