Varunkumar Jayapaul

dblp:163/4143 · DBLP profile ↗
← Back
7ranked-venue papers
4as first author
2since 2021 · last 2024
0000-0003-4027-4172ORCID · verified

Domains — the database's venue-derived domains; a paper can count in several

Theory of computation · 7 · 4 first-author · 2 since 2021
YearPublicationVenuePosition
2024 Energy efficient sorting, selection and searching
Varunkumar Jayapaul, Seungbum Jo, Krishna V. Palem, S. Srinivasa Rao 0001
Theor. Comput. Sci.1
2022 Finding kings in tournaments
abstract
A tournament is an orientation of a complete graph. It is well-known that any tournament has a vertex from which every other vertex can be reached by a path of length at most 2. Such a vertex is called a king or a 2-king. It is also known that to find such a vertex, Ωn4/3 queries (to the adjacency matrix) are necessary and On3/2 probes are sufficient. It is a long standing open problem to narrow this gap between the upper and lower bound. We first show that – the adversary Ajtai et al. (2016) and Shen et al. (2003) used to prove the known Ωn4/3 lower bound cannot be used to prove a better lower bound, by giving an algorithm that achieves the bound against the same adversary; Clearly in any tournament there is a vertex from which every other vertex is reachable by a path of length at most d for any d≥2 and such a vertex is called a d-king. The bounds for finding a 2-king have been generalized (Ajtai et al., 2016) to obtain generalized upper and lower bounds to find a d-king. We show that – our algorithm against the weak adversary works against such an adversary for finding d-kings too. More generally, if we can find a 2-king in On4/3 time, then we can find a d-king in asymptotically optimal time for any d≥2. This was conjectured in an earlier paper. Then we address the complexity of finding a set of d-kings, i.e. a small subset of vertices such that every vertex is reachable from one of them by a path of length at most d. Such a set is called a d-cover. – We generalize the lower bound for finding a d-king to give a lower bound for finding k sized d-covers. We complement it with an algorithm matching this bound for k∈Ω(lgn). For d=1 for example, our results imply that we can find a (lgn−lglgn+k)-sized dominating set in On2/k time and that this bound is optimal. Finally we develop a dynamic data structure so that whenever a new vertex is added to the tournament, we can find a king of the new tournament in O(n) time.
Arindam Biswas 0001, Varunkumar Jayapaul, Venkatesh Raman 0001, S. Srinivasa Rao 0001
Discret. Appl. Math.2
2020 Elusiveness of finding degrees
Dishant Goyal, Varunkumar Jayapaul, Venkatesh Raman 0001
Discret. Appl. Math.2
2018 Minimum Transactions Problem
Niranka Banerjee, Varunkumar Jayapaul, S. Srinivasa Rao 0001
COCOON2
2017 Finding modes with equality comparisons
Varunkumar Jayapaul, J. Ian Munro, Venkatesh Raman 0001, S. Srinivasa Rao 0001
Theor. Comput. Sci.1
2015 Sorting and Selection with Equality Comparisons
Varunkumar Jayapaul, J. Ian Munro, Venkatesh Raman 0001, S. Srinivasa Rao 0001
WADS1
2014 Space Efficient Data Structures for Nearest Larger Neighbor
Varunkumar Jayapaul, Seungbum Jo, Venkatesh Raman 0001, S. Srinivasa Rao 0001
IWOCA1