Complexity and approximability of the happy set problem (vol 866, pg 123, 2021)

For a graph G = (V, E) and a subset S subset of V of vertices, a vertex is happy if all its neighbor vertices in G are contained in S. Given a connected undirected graph and an integer k, the Maximum Happy Set Problem (MaxHS) asks to find a set S of k vertices which maximizes the number of happy vertices in S (note that all happy vertices in V belong to S). We proposed an algorithm for MaxHS on proper interval graphs in Theor. Comput. Sci. 866 (2021) 123-144. However, due to a wrong observation made by the authors, it works only on proper interval graphs obeying the observation. In this corrigendum, we propose a new algorithm which runs in O(k vertical bar V vertical bar log k + vertical bar E vertical bar) time for proper interval graphs. (c) 2023 Elsevier B.V. All rights reserved.