A Simple Linear-Time Modular Decomposition Algorithm

The first polynomial time algorithm (O(n)) for modular decomposition appeared in 1972 [8] and since then there have been incremental improvements, eventually resulting in linear-time algorithms [22, 7, 23, 9]. Although having optimal time complexity these algorithms are quite complicated and difficult to implement. In this paper we present an easily implementable linear-time algorithm for modular decomposition. This algorithm uses the notion of factorizing permutation and a new data-structure, the Ordered Chain Partitions.