On the closest string and substring problems
Journal of the ACM (JACM)
A Linear-Time Algorithm for the 1-Mismatch Problem
WADS '97 Proceedings of the 5th International Workshop on Algorithms and Data Structures
Banishing Bias from Consensus Sequences
CPM '97 Proceedings of the 8th Annual Symposium on Combinatorial Pattern Matching
Genetic Algorithm Approach for the Closest String Problem
CSB '03 Proceedings of the IEEE Computer Society Conference on Bioinformatics
Distinguishing string selection problems
Information and Computation
Optimal Solutions for the Closest-String Problem via Integer Programming
INFORMS Journal on Computing
Efficient Algorithms for the Closest String and Distinguishing String Selection Problems
FAW '09 Proceedings of the 3d International Workshop on Frontiers in Algorithmics
Closest Substring Problems with Small Distances
SIAM Journal on Computing
Complexities of the centre and median string problems
CPM'03 Proceedings of the 14th annual conference on Combinatorial pattern matching
More Efficient Algorithms for Closest String and Substring Problems
SIAM Journal on Computing
IEEE/ACM Transactions on Computational Biology and Bioinformatics (TCBB)
Space and time efficient algorithms for planted motif search
ICCS'06 Proceedings of the 6th international conference on Computational Science - Volume Part II
Parameterized Complexity
The parameterized complexity of the shared center problem
CPM'12 Proceedings of the 23rd Annual conference on Combinatorial Pattern Matching
Enumerating neighbour and closest strings
IPEC'12 Proceedings of the 7th international conference on Parameterized and Exact Computation
An efficient two-phase ant colony optimization algorithm for the closest string problem
SEAL'12 Proceedings of the 9th international conference on Simulated Evolution and Learning
On approximating string selection problems with outliers
Theoretical Computer Science
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Given a set of n strings of length L and a radius d, the closest string problem (CSP for short) asks for a string t"s"o"l that is within a Hamming distance of d to each of the given strings. It is known that the problem is NP-hard and its optimization version admits a polynomial time approximation scheme (PTAS). Parameterized algorithms have been then developed to solve the problem when d is small. In this paper, with a new approach (called the 3-string approach), we first design a parameterized algorithm for binary strings that runs in O(nL+nd^3@?6.731^d) time, while the previous best runs in O(nL+nd@?8^d) time. We then extend the algorithm to arbitrary alphabet sizes, obtaining an algorithm that runs in time O(nL+nd@?(1.612(|@S|+@b^2+@b-2))^d), where |@S| is the alphabet size and @b=@a^2+1-2@a^-^1+@a^-^2 with @a=|@S|-1+13. This new time bound is better than the previous best for small alphabets, including the very important case where |@S|=4 (i.e., the case of DNA strings).