How do I approach Coding & Algorithms interview questions?

Coding & Algorithms questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master coding & algorithms interviews.

What difficulty level is this interview question?

This is a medium difficulty Coding & Algorithms question, commonly asked during Onsite rounds at Atlassian.

What role is this question designed for?

This question is commonly asked for Machine Learning Engineer candidates at Atlassian during technical interviews.

Compute inverse-depth weighted sum of a nested list

Quick Overview

This question evaluates competency in working with nested data structures and depth-based aggregation, measuring the ability to reason about hierarchical list contents and weighted summation; it falls under the Coding & Algorithms domain and targets practical implementation skills rather than purely theoretical understanding.

Problem

You are given a nested list of integers, where each element is either:

an integer, or
a list that follows the same rule (i.e., a nested list).

Define the depth of an integer as the number of lists that contain it.

Example: In [1,[2,[3]]] , the integer 1 has depth 1, 2 has depth 2, and 3 has depth 3.

Let D be the maximum depth among all integers in the structure. Compute the inverse-depth weighted sum where each integer with depth d is weighted by:

$weight(d) = D - d + 1$

Return the total weighted sum.

Examples

Input: [1,[2,[3]]]
- Maximum depth D=3
- Sum = 1*(3-1+1) + 2*(3-2+1) + 3*(3-3+1) = 1*3 + 2*2 + 3*1 = 10
- Output: 10
Input: [[1,1],2,[1,1]]
- Maximum depth D=2
- Output: 8

Constraints (reasonable interview constraints)

Total number of integers N up to ~1e4.
Total nested list elements (including lists) up to ~1e4.
Integers fit in 32-bit signed range.

Function Signature (language-agnostic)

int inverseDepthSum(NestedList nested)

Compute inverse-depth weighted sum of a nested list

Quick Overview