An optimal algorithm for the longest common subsequence problem

The longest common subsequence problem is to find a longest common subsequence of two given strings. The complexity of this problem on the decision tree model is known as mn, where m and n are the lengths of these two strings, respectively, and m⩽n. The authors present a parallel algorithm for this problem on the CREW PRAM model, which takes O(log²mloglogm) time with mn/log²mloglogm processors when log²mloglogm>logn, or otherwise O(logn) time with mn logn processors