Two Numbers With Sum Closest to Zero

Problem
Given an array of integers (positive and negative), find the pair whose sum is closest to zero.

Input / Output

• Input: integer array nums (mix of positive and negative values).
• Output: the pair (or its sum) with the smallest absolute sum.

Constraints

• 2 <= n <= 10^5; aim to beat the O(n^2) all-pairs check.

Example

• [1, 60, -10, 70, -80, 85] → (-80, 85), sum 5.