Fast sequential and parallel algorithms for finding the largest rectangle separating two sets
Given a bounding isothetic rectangle BR and two sets of points A and B with cardinalities n and m inside it, we have to find an isothetic rectangle containing maximum number of points from set A and no point from set B. We consider two limiting cases of this problem when the cardinalities of set A (...
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| Published in: | International journal of computer mathematics Vol. 37; no. 1-2; pp. 49 - 61 |
|---|---|
| Main Authors: | , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Abingdon
Gordon and Breach Science Publishers
01.01.1990
Taylor and Francis |
| Subjects: | |
| ISSN: | 0020-7160, 1029-0265 |
| Online Access: | Get full text |
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| Summary: | Given a bounding isothetic rectangle BR and two sets of points A and B with cardinalities n and m inside it, we have to find an isothetic rectangle containing maximum number of points from set A and no point from set B. We consider two limiting cases of this problem when the cardinalities of set A (resp. set B) is much greater than that of set B (resp. set ,A). We present efficient sequential and parallel algorithms for these two problems. Our sequential algorithms run in O((n + m)log m + m
2
) and O((m+ n) log n + n
2
) time respectively. The parallel algorithms in CREW PRAM run in o(log n) ando(log m
2
) time using O(max(n,m
2
/logm)) and O(max(m,n
2
/logn)) processors respectively. Our sequential algorithms are faster than a previous algorithm under these constraints on cardinality. No previous parallel algorithm was known for this problem. We also present an optimal systolic algorithm for the original problem. |
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| ISSN: | 0020-7160 1029-0265 |
| DOI: | 10.1080/00207169008803934 |