Edit: question simplified to remove confusion
Assuming a sorted list of items with indexes from 1 to
N, and given only an index number
i and the maximum index
N, is there a simple function which will return the two possible indexes that would be reached next in a binary search of the list?
i = 6 N = 8 LeftSearchIndex(i, N) = 5 RightSearchIndex(i, N) = 7