The minmax regret permutation flow-shop problem with two jobs

We consider the makespan-minimizing permutation flow-shop problem with 2 jobs and m machines and uncertain processing times of operations. For each operation, an uncertainty interval is given, and it is assumed that the processing time of each operation can take on any value from the corresponding uncertainty interval, regardless of the values taken by processing times of other operations. For the problem of finding a minmax regret solution, we present an O(m) algorithm.