Search Results

Finding the minimal-cost closed loop on a weighted graph where every vertex is visited exactly once is known as the Travelling Salesperson Problem (TSP). In a recently proposed variant, TSP with Self-Deleting graphs (TSP-SD), visiting a vertex i deletes a set of edges in the graph, preventing their subsequent traversal. Due to the dependency between vertex visits and edge deletion, in TSP-SD the feasibility of a cycle depends on the start node. The best performing solution approaches in the literature rely on a simple problem reformulation to find a backward tour where vertex visits add edges rather than delete them. This paper investigates exact model-based approaches, specifically Constraint Programming (CP), Domain-Independent Dynamic Programming (DIDP), and Mixed Integer Linear Programming (MIP) to solve TSP-SD. We show that simple preprocessing can substantially reduce the options for start/end vertex pairs but typically has a limited positive impact on search performance. Our numerical results demonstrate that the difference between the deletion and addition variants is small for CP and MIP but that the reformulation is critical for DIDP performance. Overall, the DIDP addition model is the best of the exact methods on all test instances and outperforms existing heuristic solvers for small and medium-sized instances while trailing in terms of solution quality on larger instances.