Dynamic rank-maximal matchings

Abstract

We consider the problem of matching applicants to posts where applicants have preferences over posts. Thus the input to our problem is a bipartite graph (formula presented), where \mathcal {A} denotes a set of applicants, \mathcal {P} is a set of posts, and there are ranks on edges which denote the preferences of applicants over posts. A matching M in G is called rank-maximal if it matches the maximum number of applicants to their rank in a dynamic setting, where vertices and edges can be added and deleted at any point. Let n and m be the number of vertices and edges in an instance G, and r be the maximum rank used by any rank-maximal matching in G. We give a simple O(r(m+n)) -time algorithm to update an existing rank-maximal matching under each of these changes. When r=o(n), this is faster than recomputing a rank-maximal matching completely using a known algorithm like that of Irving et al. [13], which takes time (formula presented).