מושגי ליבה
This article presents the first algorithm that runs in O(n log n) time in the worst case for the Signed Sorting by Reversals problem, which transforms a signed permutation into the identity permutation using a minimum-length sequence of reversals.
תקציר
The article presents an efficient algorithm for the Signed Sorting by Reversals problem, which involves transforming a signed permutation into the identity permutation using a minimum-length sequence of reversals.
The key highlights and insights are:
- The algorithm runs in O(n log n) time in the worst case, improving upon the previous best algorithm with a running time of O(n log^2 n/ log log n).
- The algorithm is relatively simple to implement and has low hidden constants.
- The algorithm is based on a binary search tree data structure that efficiently maintains the state of the permutation and its components through each reversal.
- The algorithm uses a recovery scheme to handle cases where no good reversal is available, by backtracking and inserting new good reversals at appropriate points.
- The article provides a thorough theoretical analysis of the algorithm's correctness and efficiency, building upon previous work by Tannier et al.