Two pointers: exploit sorted order with two coordinated indexes

Two pointers: Given nums and target, choose two distinct elements and return the minimum absolute difference between their sum and target. Return null when fewer than two elements are available.

Input: A JSON object { "nums": number[], "target": number }.

Output: A JSON number for the minimum absolute difference, or null when no pair exists.

Constraints:

0 <= nums.length <= 100000
nums may be unsorted and may contain duplicates
A pair must use two distinct indexes

Read one JSON value from stdin and print exactly one JSON-serialized answer to stdout with no extra text.

Difficulty: HARD. Variant: 18. Favor a pragmatic solution that is easy to ship, read, and adapt.

Practice context

This coding (algo) exercise trains prompt interpretation, explicit assumptions, a concrete response, and a concise explanation of the decisions made. It is marked hard difficulty.

The signed-in

What this task practices

This coding (algo) exercise trains the same sequence expected in an interview: understand the prompt, make assumptions explicit, produce a concrete answer, and explain the decisions behind it. The task is marked hard difficulty. The private workspace adds the tools required by this round, such as recording, code execution, diagrams, evidence panels, or structured notes. It also preserves the attempt so later feedback can be compared with previous work. Evaluation is based on task-specific criteria and the candidate seniority selected in the preparation path. Public pages never expose the reference solution, hidden tests, evaluator instructions, or another candidate’s work.