CodingMediumcod-g072

Subject Two pointersLevel Mid–Senior~20 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given an integer array a (possibly with negatives, length >= 2) and an integer target, pick two distinct elements whose sum is closest to target. Return that sum (the value of the closest sum, not the indices). If two sums are equally close, return either.

Implement

closest_pair_sum(a: list[int], target: int) → int

Examples

in[[1,2,3,4,5],8]out8

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.