An r-gathering of customers C to facilities F is an assignment A of C to open facilities F' ⊂ F such that r (≥ 2) or more customers are assigned to each open facility. (Each facility needs enough number of customers for its opening.) Then the r-gathering problem finds an r-gathering minimizing a designated cost. Armon gave a simple 3-approximation algorithm for the r-gathering problem and proved that with assumption P ≠ NP the problem cannot be approximated within a factor of less than 3 for any r ≥ 3. The running time of the 3-approximation algorithm is O(|C||F|+r|C|+|C|log|C|)). In this paper we improve the running time of the algorithm by (1) removing the sort in the algorithm and (2) designing a simple but efficient data structure.
Toshihiro AKAGI
Gunma University
Ryota ARAI
Gunma University
Shin-ichi NAKANO
Gunma University
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Toshihiro AKAGI, Ryota ARAI, Shin-ichi NAKANO, "Faster Min-Max r-Gatherings" in IEICE TRANSACTIONS on Fundamentals,
vol. E99-A, no. 6, pp. 1149-1151, June 2016, doi: 10.1587/transfun.E99.A.1149.
Abstract: An r-gathering of customers C to facilities F is an assignment A of C to open facilities F' ⊂ F such that r (≥ 2) or more customers are assigned to each open facility. (Each facility needs enough number of customers for its opening.) Then the r-gathering problem finds an r-gathering minimizing a designated cost. Armon gave a simple 3-approximation algorithm for the r-gathering problem and proved that with assumption P ≠ NP the problem cannot be approximated within a factor of less than 3 for any r ≥ 3. The running time of the 3-approximation algorithm is O(|C||F|+r|C|+|C|log|C|)). In this paper we improve the running time of the algorithm by (1) removing the sort in the algorithm and (2) designing a simple but efficient data structure.
URL: https://global.ieice.org/en_transactions/fundamentals/10.1587/transfun.E99.A.1149/_p
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@ARTICLE{e99-a_6_1149,
author={Toshihiro AKAGI, Ryota ARAI, Shin-ichi NAKANO, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={Faster Min-Max r-Gatherings},
year={2016},
volume={E99-A},
number={6},
pages={1149-1151},
abstract={An r-gathering of customers C to facilities F is an assignment A of C to open facilities F' ⊂ F such that r (≥ 2) or more customers are assigned to each open facility. (Each facility needs enough number of customers for its opening.) Then the r-gathering problem finds an r-gathering minimizing a designated cost. Armon gave a simple 3-approximation algorithm for the r-gathering problem and proved that with assumption P ≠ NP the problem cannot be approximated within a factor of less than 3 for any r ≥ 3. The running time of the 3-approximation algorithm is O(|C||F|+r|C|+|C|log|C|)). In this paper we improve the running time of the algorithm by (1) removing the sort in the algorithm and (2) designing a simple but efficient data structure.},
keywords={},
doi={10.1587/transfun.E99.A.1149},
ISSN={1745-1337},
month={June},}
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TY - JOUR
TI - Faster Min-Max r-Gatherings
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 1149
EP - 1151
AU - Toshihiro AKAGI
AU - Ryota ARAI
AU - Shin-ichi NAKANO
PY - 2016
DO - 10.1587/transfun.E99.A.1149
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E99-A
IS - 6
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - June 2016
AB - An r-gathering of customers C to facilities F is an assignment A of C to open facilities F' ⊂ F such that r (≥ 2) or more customers are assigned to each open facility. (Each facility needs enough number of customers for its opening.) Then the r-gathering problem finds an r-gathering minimizing a designated cost. Armon gave a simple 3-approximation algorithm for the r-gathering problem and proved that with assumption P ≠ NP the problem cannot be approximated within a factor of less than 3 for any r ≥ 3. The running time of the 3-approximation algorithm is O(|C||F|+r|C|+|C|log|C|)). In this paper we improve the running time of the algorithm by (1) removing the sort in the algorithm and (2) designing a simple but efficient data structure.
ER -