Nested List Weight Sum

Problem

Given a nested list of integers, return the sum where each integer is weighted by its depth (top-level depth = 1, one level deeper = 2, and so on).

Input / Output

• Input: a nested list, where each element is either an integer or another nested list.
• Output: the depth-weighted sum of all integers.

Constraints

• Arbitrary nesting depth.

Example

[[1,1],2,[1,1]] -> 1*2+1*2+2*1+1*2+1*2 = 10