Bing-Chao Huang
Michael A. Langston
Abstract
We present a novel, yet straightforward linear-time algorithm for merging two sorted lists in a fixed amount of additional space. Constant of proportionality estimates and empirical testing reveal that this procedure is reasonably competitive with merge routines free to squander unbounded additional memory, making it particularly attractive whenever space is a critical resource.
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Index Terms
- Practical in-place merging
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ACM '87: Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrowWe present a novel, yet straightforward linear-time algorithm for merging two sorted lists in a fixed amount of additional space. Constant of proportionality estimates and empirical testing reveal that this procedure is reasonably competitive with merge ...
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Reviews
Snehamay Bandyapadhyay
The authors have presented an interesting algorithm for in-place merging of two sorted lists. The paper is well written: section 2 presents an especially clear and easy-to-understand overview of the main algorithm. To merge a total of n records contained in two sorted lists, the authors use O(:.PC9 :3WzL n) blocks, each of size O(:.PC9 :3WzL n). The blocks are first arranged and then, using one block as an internal buffer, the records are merged by passing the internal buffer across the list. The paper also contains a section on implementation details that is sufficient to implement the algorithm. The authors agree that the algorithm is not stable and refer to a modified version of the algorithm, which is stable. They claim that the modified algorithm is faster than existing algorithms, but the claim is not substantiated in this paper. This paper will be of interest to any reader interested in merging of files; however, a casual reader may be advised to skip section 3. Finally, the algorithm is simple but not as simple as the authors claim it to be.
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