2963	 A Fast Algorithm for Computing Longest Common Subsequences	 Previously published algorithms for finding the longest common subsequence of two sequences of length n have had a best-case running time of O n . An algorithm for this problem is presented which has a running time of O r n log n where r is the total number of ordered pairs of positions at which the two sequences match. Thus in the worst case the algorithm has a running time of O n log n . However for those applications where most positions of one sequence match relatively few positions in the other sequence a running time of O n log n can be expected. Longest common subsequence efficient algorithms
