the Priority Line Algorithm for priority order (p2, p1, p3, p4). the Priority Line Algorithm for priority order (p1, p2, p4, p3). House Allocation Problem a standard house allocation problem with three agents (p1, p2 and p3) and three houses C). struct preferences for p1, p2 and p3 such that a Pareto efficient assignment is unique. struct preferences for p1, p2 and p3 such that any assignment is Pareto efficient