MétaCan
Menu
Back to cohort
Record W2607184796 · doi:10.1137/1.9781611975062.2

Quicksort Is Optimal For Many Equal Keys

2018· book-chapter· en· W2607184796 on OpenAlexaff
Sebastian Wild

Bibliographic record

VenueSociety for Industrial and Applied Mathematics eBooks · 2018
Typebook-chapter
Languageen
FieldMathematics
TopicLimits and Structures in Graph Theory
Canadian institutionsUniversity of Waterloo
Fundersnot available
KeywordsQuicksortCombinatoricsConstant (computer programming)MathematicsSortingConjectureAsymptotically optimal algorithmUpper and lower boundsValue (mathematics)Discrete mathematicsSorting algorithmAlgorithmComputer scienceStatisticsMathematical analysis

Abstract

fetched live from OpenAlex

I prove that the average number of comparisons for median-of-k Quicksort (with fat-pivot a.k.a. three-way partitioning) is asymptotically only a constant αk times worse than the lower bound for sorting random multisets of n elements with Ω(n∊) duplicates of each value (for any ∊ > 0). The constant is αk = ln(2)/(Hk+1 – H(k+1)/2), which converges to 1 as k → ∞, so median-of-k Quicksort is asymptotically optimal for inputs with many duplicates. This partially resolves a conjecture by Sedgewick and Bentley (1999, 2002) and constitutes the first progress on the analysis of Quicksort with equal elements since Sedgewick's 1977 article.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.003
metaresearch head score (Gemma)0.030
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: Theoretical or conceptual
GenreCandidate signal: Methods · Consensus signal: none
Teacher disagreement score0.018
Threshold uncertainty score0.059

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0030.030
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0020.002
Bibliometrics0.0010.003
Science and technology studies0.0030.003
Scholarly communication0.0060.019
Open science0.0030.004
Research integrity0.0020.004
Insufficient payload (model declined to judge)0.0180.004

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.107
GPT teacher head0.296
Teacher spread0.189 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designTheoretical or conceptual
Domainnot available
GenreMethods

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations4
Published2018
Admission routes1
Has abstractyes

Explore more

Same venueSociety for Industrial and Applied Mathematics eBooksSame topicLimits and Structures in Graph TheoryFrench-language works237,207