>Your problem is (fairly) well defined and the answer is a binary search.
>"Binary Search" usually refers to an algorithm that finds a specific member of an ordered (sorted) random-access array. That's not the setup here.
Or, a bit more precisely, an indexed set with direct access via ordered index, values sorted by index. For indices i,j; i > j => v(i) > v(j) (or vica versa).
