Code Room
CodingHardcod-g061
Subject Fenwick treeLevel Senior–Staff~35 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given an integer array `nums`, return an array `counts` where `counts[i]` is the number of elements to the RIGHT of index i that are strictly smaller than `nums[i]`. Aim for O(n log n). Values may be negative and may repeat. `0 <= len(nums) <= 100000`, `-10^9 <= nums[i] <= 10^9`.

Implement
count_smaller_after(nums: list[int]) → list[int]
Examples
in[[5,2,6,1]]out[2,1,1,0]
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.