This is similar to https://leetcode.com/problems/random-pick-with-weight/, but we\'re not just picking an index here, we need to also pop it from the data structure. We also have to implement a push operation. Both of these operations have complexity better than O(n) time. \n\nIt seems a segment tree or BIT would work here?

This is similar to https://leetcode.com/problems/random-pick-with-weight/, but we\'re not just picking an index here, we need to also pop it from the data struc