Yota OTACHI


On Computational Complexity of Pipe Puzzles
Takumu SHIRAYAMA Takuto SHIGEMURA Yota OTACHI Shuichi MIYAZAKI Ryuhei UEHARA 
Publication:   
Publication Date: 2019/09/01
Vol. E102-A  No. 9  pp. 1134-1141
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: Puzzles
Keyword: 
pipe puzzleNP-completenesspolynomial-time algorithm
 Summary | Full Text:PDF(7MB)

Secure Sets and Defensive Alliances in Graphs: A Faster Algorithm and Improved Bounds
Kazuyuki AMANO Kyaw May OO Yota OTACHI Ryuhei UEHARA 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2015/03/01
Vol. E98-D  No. 3  pp. 486-489
Type of Manuscript:  Special Section PAPER (Special Section on Foundations of Computer Science---New Spirits in Theory of Computation and Algorithm---)
Category: 
Keyword: 
secure setdefensive alliancefixed-parameter tractabilityhypercube
 Summary | Full Text:PDF(267.1KB)

Enumerating All Rooted Trees Including k Leaves
Masanobu ISHIKAWA Katsuhisa YAMANAKA Yota OTACHI Shin-ichi NAKANO 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2012/03/01
Vol. E95-D  No. 3  pp. 763-768
Type of Manuscript:  Special Section PAPER (Special Section on Foundations of Computer Science – Mathematical Foundations and Applications of Computer Science and Algorithms –)
Category: 
Keyword: 
graph algorithmenumerationrooted treefamily tree
 Summary | Full Text:PDF(258.3KB)