Heap-based topk can compute these indices in O(n log k) time

Reporter: Wes McKinney / @wesm
Assignee: Alexander Ocsa / @aocsa

Related issues:

• [C++] Resolve follow-up reviews for TopK/BottomK (is a parent of)
• [C++] Query engine umbrella issue (is a child of)
• [C++] Improve select_k_unstable performance (is related to)
• [R] Add Arrow methods slice_min(), slice_max() (is depended upon by)

PRs and other links:

• GitHub Pull Request #11019

_{Note: This issue was originally created as ARROW-1565. Please see the migration documentation for further details.}