CodingMediumcod-g573

Subject ArraysLevel Mid–Senior~18 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given an integer array nums and an integer k (k >= 0), return the number of UNIQUE pairs of distinct array positions whose values differ by exactly k. A pair is identified by its value pair, so (1,3) counts once even if 1 or 3 repeats. For k = 0, count values that appear at least twice. Array length up to 1e4.

Implement

count_pairs_diff(nums: list[int], k: int) → int

Examples

in[[3,1,4,1,5],2]out2

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.

Learn the concepts

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.