This is a problem based on binary search and bit manipulation, as the constraint are very large, the brute force doesnt work. How to apply D&C ??
https://practice.geeksforgeeks.org/problems/akku-and-binary-numbers/0
D&C Bit manipulation
Think in terms of P&C
once u set the left most bit, out of the remaining bits u just have to choose any 2 bits to set which is single step nc2
just u have to mind for numbers which are less than r and greater than l
those cases could be handled separately