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Programming · Easy

All Pairs

Supported standard problem · Match confidence: high

Jane Street · Topic guidanceCitadel · Topic guidanceCitadel Securities · Topic guidance
About this question’s source match

The title and Programming / Array and List Processing classification fit the linked public problem. This entry uses an independently worded practice statement and original implementation. Public catalogue example was read directly. Sorting the output is an added deterministic Learnr convention.

Implement solve(nums,target), returning every distinct pair of values with sum target. Use two different array positions; order within a pair is ascending. Return pairs lexicographically sorted.

Assumptions and constraints

  • Integers may repeat and may be negative.
  • 0 <= n <= 1000000

Examples

nums=[2,2,3,5,-1], target=4
→ [
  [
    -1,
    5
  ],
  [
    2,
    2
  ]
]

Two separate copies of 2 permit pair (2,2).

Company preparation relevance

These links connect this exercise to companies’ public examples or stated interview topics. They do not establish that a company asked this exact Learnr question.

  • Jane Street

    Official topic guidance

    Topic overlap: implementing and explaining a value-pair algorithm exercises the coding/problem-solving skills in the official engineering preparation guidance.

    Preparing for a Software Engineering Interview ↗
    Evidence scope and uncertainty

    Software engineering preparation only; not a claim that Jane Street asks two-sum or our “All Pairs” exercise.

    These are Learnr-authored exercises selected for topic overlap. The company does not name these catalogue titles or verify that these exact questions were asked.

  • Citadel

    Official topic guidance

    Topic overlap: pair searching “All Pairs”, graph shortest paths “Dijkstra's Algorithm #1”, linked-list cycles “Linked List Cycle” and heaps “Priority Queue Using Heaps” provide coding/data-structure/algorithm practice matching the stated campus research interview focus.

    Our Campus Quantitative Research Interview Process ↗
    Evidence scope and uncertainty

    Official guide dated 9 November 2024; explicitly describes Citadel and Citadel Securities together. Role/date specific; no present universal timing asserted.

    These are Learnr-authored exercises selected for topic overlap. The company does not name these catalogue titles or verify that these exact questions were asked.

  • Citadel Securities

    Official topic guidance

    Topic overlap: pair search “All Pairs”, shortest paths “Dijkstra's Algorithm #1”, linked lists “Linked List Cycle”, heaps “Priority Queue Using Heaps” and streaming median “Streaming Median” exercise programming, data structures and algorithms. The official guide explicitly covers both Citadel and Citadel Securities.

    Our Campus Quantitative Research Interview Process ↗
    Evidence scope and uncertainty

    Shared campus quantitative research guide dated 9 November 2024. This does not transfer every Citadel job requirement to Citadel Securities or establish an engineering-specific process.

    These are Learnr-authored exercises selected for topic overlap. The company does not name these catalogue titles or verify that these exact questions were asked.

References

Read the supporting material without leaving your question.

Catalogue metadata captured 2026-10-12. Metadata source.