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- Publications
- Influence

Deciding k-Colorability of P5-Free Graphs in Polynomial Time

- C. Hoàng, M. Kaminski, V. Lozin, J. Sawada, Xiao Shu
- Computer Science, Mathematics
- Algorithmica
- 7 February 2007

The problem of computing the chromatic number of a P5-free graph (a graph which contains no path on 5 vertices as an induced subgraph) is known to be NP-hard. However, we show that for every fixed… Expand

An efficient algorithm for generating necklaces with fixed density

A k-ary necklace is an equivalence class of k-ary strings under rotation. A necklace of fixed density is a necklace where the number of zeros is fixed. We present a fast, simple, recursive algorithm… Expand

Generating Bracelets in Constant Amortized Time

- J. Sawada
- Computer Science, Mathematics
- SIAM J. Comput.
- 2001

A bracelet is the lexicographically smallest element in an equivalence class of strings under string rotation and reversal. We present a fast, simple, recursive algorithm for generating (i.e.,… Expand

Constructions of k-critical P5-free graphs

- C. Hoàng, B. Moore, D. Recoskie, J. Sawada, M. Vatshelle
- Mathematics, Computer Science
- Discret. Appl. Math.
- 19 February 2015

With respect to a hereditary class C of graphs, a k -chromatic graph G ? C is said to be k -critical if every proper subgraph of G belonging to C is k - 1 colorable. It is known that there is a… Expand

A Hamilton Path for the Sigma-Tau Problem

- J. Sawada, A. Williams
- Computer Science
- SODA
- 7 January 2018

Nijenhuis and Wilf asked the following question in their Combinatorial Algorithms textbook from 1975: Can the permutations of {1, 2,...,n} be ordered so that each permutation is transformed into the… Expand

Fast Algorithms to Generate Necklaces, Unlabeled Necklaces, and Irreducible Polynomials over GF(2)

- K. Cattell, F. Ruskey, J. Sawada, M. Serra, C. Miers
- Mathematics, Computer Science
- J. Algorithms
- 1 November 2000

Many applications call for exhaustive lists of strings subject to various constraints, such as inequivalence under group actions. A k-ary necklace is an equivalence class of k-ary strings under… Expand

A Certifying Algorithm for 3-Colorability of P5-Free Graphs

- Daniel Bruce, C. Hoàng, J. Sawada
- Computer Science, Mathematics
- ISAAC
- 20 July 2009

We provide a certifying algorithm for the problem of deciding whether a P 5-free graph is 3-colorable by showing there are exactly six finite graphs that are P 5-free and not 3-colorable and minimal… Expand

A fast algorithm to generate necklaces with fixed content

- J. Sawada
- Mathematics, Computer Science
- Theor. Comput. Sci.
- 14 May 2003

We develop a fast algorithm for listing all necklaces with fixed content. By fixed content, we mean the number of occurrences of each alphabet symbol is fixed. Initially, we construct a simple but… Expand

De Bruijn Sequences for Fixed-Weight Binary Strings

- F. Ruskey, J. Sawada, A. Williams
- Mathematics, Computer Science
- SIAM J. Discret. Math.
- 8 May 2012

De Bruijn sequences are circular strings of length $2^n$ whose length n substrings are the binary strings of length n. Our focus is on creating circular strings of length $\binom{n}{w}$ for the… Expand

On Prefix Normal Words and Prefix Normal Forms

- Peter Burcsi, G. Fici, Z. Lipták, F. Ruskey, J. Sawada
- Computer Science, Mathematics
- Theor. Comput. Sci.
- 28 November 2016

Abstract A 1-prefix normal word is a binary word with the property that no factor has more 1s than the prefix of the same length; a 0-prefix normal word is defined analogously. These words arise in… Expand