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An industrial grade Quicksort function along with its new algorithm is presented. Compared to 4 other well known implementations of Quicksort, the new algorithm reduces both the number of comparisons and swaps in most cases while staying…

Data Structures and Algorithms · Computer Science 2015-05-12 Ammar Muqaddas

The number of comparisons X_n used by Quicksort to sort an array of n distinct numbers has mean mu_n of order n log n and standard deviation of order n. Using different methods, Regnier and Roesler each showed that the normalized variate…

Probability · Mathematics 2007-05-23 James Allen Fill , Svante Janson

Bitmap indexes must be compressed to reduce input/output costs and minimize CPU usage. To accelerate logical operations (AND, OR, XOR) over bitmaps, we use techniques based on run-length encoding (RLE), such as Word-Aligned Hybrid (WAH)…

Databases · Computer Science 2016-08-02 Daniel Lemire , Owen Kaser , Kamel Aouiche

While modern general-purpose computing systems have ample amounts of memory, it is still the case that embedded computer systems, such as in a refrigerator, are memory limited; hence, such embedded systems motivate the need for strictly…

Data Structures and Algorithms · Computer Science 2026-03-09 Ofek Gila , Michael T. Goodrich , Vinesh Sridhar

This paper introduces a novel and efficient partitioning technique for quicksort, specifically designed for real-world data with duplicate elements (50-year-old problem). The method is referred to as "equal quicksort" or "eqsort". Based on…

Data Structures and Algorithms · Computer Science 2025-03-12 Parviz Afereidoon

We consider the problem of inserting a new item into an ordered list of N-1 items. The length of an algorithm is measured by the number of comparisons it makes between the new item and items already on the list. Classically, determining the…

Quantum Physics · Physics 2007-05-23 E. Farhi , J. Goldstone , S. Gutmann , M. Sipser

The limiting distribution of the normalized number of comparisons used by Quicksort to sort an array of n numbers is known to be the unique fixed point with zero mean of a certain distributional transformation S. We study the convergence to…

Probability · Mathematics 2007-05-23 James Allen Fill , Svante Janson

In our previous work there was some indication that Partition Sort could be having a more robust average case O(nlogn) complexity than the popular Quick Sort. In our first study in this paper, we reconfirm this through computer experiments…

Data Structures and Algorithms · Computer Science 2012-03-28 Niraj Kumar Singh , Mita Pal , Soubhik Chakraborty

We investigate distributed memory parallel sorting algorithms that scale to the largest available machines and are robust with respect to input size and distribution of the input elements. The main outcome is that four sorting algorithms…

Distributed, Parallel, and Cluster Computing · Computer Science 2020-01-17 Michael Axtmann , Peter Sanders

We study the impact of merging routines in merge-based sorting algorithms. More precisely, we focus on the galloping routine that TimSort uses to merge monotonic sub-arrays, hereafter called runs, and on the impact on the number of element…

Data Structures and Algorithms · Computer Science 2023-12-04 Elahe Ghasemi , Vincent Jugé , Ghazal Khalighinejad , Helia Yazdanyar

Sorting is an essential operation in computer science with direct consequences on the performance of large scale data systems, real-time systems, and embedded computation. However, no sorting algorithm is optimal under all distributions of…

Data Structures and Algorithms · Computer Science 2025-06-27 Shrinivass Arunachalam Balasubramanian

We present space efficient Monte Carlo algorithms that solve Subset Sum and Knapsack instances with $n$ items using $O^*(2^{0.86n})$ time and polynomial space, where the $O^*(\cdot)$ notation suppresses factors polynomial in the input size.…

Data Structures and Algorithms · Computer Science 2017-06-27 Nikhil Bansal , Shashwat Garg , Jesper Nederlof , Nikhil Vyas

We explore the fundamental problem of sorting through the lens of learning-augmented algorithms, where algorithms can leverage possibly erroneous predictions to improve their efficiency. We consider two different settings: In the first…

Data Structures and Algorithms · Computer Science 2023-11-03 Xingjian Bai , Christian Coester

We present sorting algorithms that represent the fastest known techniques for a wide range of input sizes, input distributions, data types, and machines. A part of the speed advantage is due to the feature to work in-place. Previously, the…

Distributed, Parallel, and Cluster Computing · Computer Science 2021-02-05 Michael Axtmann , Sascha Witt , Daniel Ferizovic , Peter Sanders

When algorithms for sorting and searching are applied to keys that are represented as bit strings, we can quantify the performance of the algorithms not only in terms of the number of key comparisons required by the algorithms but also in…

Probability · Mathematics 2009-04-16 James Allen Fill , Take Nakama

Sorting is one of the most basic algorithms, and developing highly parallel sorting programs is becoming increasingly important in high-performance computing because the number of CPU cores per node in modern supercomputers tends to…

Distributed, Parallel, and Cluster Computing · Computer Science 2023-09-08 Tomoyuki Tokuue , Tomoaki Ishiyama

In this paper, we proposed a new efficient sorting algorithm based on insertion sort concept. The proposed algorithm called Bidirectional Conditional Insertion Sort (BCIS). It is in-place sorting algorithm and it has remarkably efficient…

Data Structures and Algorithms · Computer Science 2017-08-08 Adnan Saher Mohammed , Şahin Emrah Amrahov , Fatih V. Çelebi

We empirically study sorting in the evolving data model. In this model, a sorting algorithm maintains an approximation to the sorted order of a list of data items while simultaneously, with each comparison made by the algorithm, an…

Data Structures and Algorithms · Computer Science 2018-05-16 Juan Jose Besa , William E. Devanny , David Eppstein , Michael Goodrich , Timothy Johnson

We present four high performance hybrid sorting methods developed for various parallel platforms: shared memory multiprocessors, distributed multiprocessors, and clusters taking advantage of existence of both shared and distributed memory.…

Distributed, Parallel, and Cluster Computing · Computer Science 2020-03-04 Thoria Alghamdi , Gita Alaghband

Given a sequence of $n$ numbers and $k$ parallel First-in-First-Out (FIFO) queues, how close can one bring the sequence to sorted order? It is known that $k$ queues suffice to sort the sequence if the Longest Decreasing Subsequence (LDS) of…

Data Structures and Algorithms · Computer Science 2025-09-17 Andreas Karrenbauer , Kurt Mehlhorn , Pranabendu Misra , Paolo Luigi Rinaldi , Anna Twelsiek , Alireza Haqi , Siavash Rahimi Shateranloo