Routing and scheduling on a shoreline with release times
Management Science
Approximation algorithms for NP-hard problems
Approximation algorithms for NP-hard problems
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Constrained TSP and Low-Power Computing
WADS '97 Proceedings of the 5th International Workshop on Algorithms and Data Structures
Discrete Applied Mathematics
Strip packing with precedence constraints and strip packing with release times
Proceedings of the eighteenth annual ACM symposium on Parallelism in algorithms and architectures
Strip packing with precedence constraints and strip packing with release times
Theoretical Computer Science
Improved approximation algorithms for routing shop scheduling
ISAAC'11 Proceedings of the 22nd international conference on Algorithms and Computation
Theoretical Computer Science
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We consider makespan minimization for vehicle scheduling problems on trees with job requests that have release and handling times. 2-approximation algorithms were known for several variants of the single vehicle problem on a path. A 3/2-approximation algorithm was known for the single vehicle problem on a path where there is a fixed starting point and the vehicle must return to the starting point upon completion. Karuno, Nagamochi and Ibaraki give a 2-approximation algorithm for the single vehicle problem on trees. We develop a polynomial time approximation scheme (PTAS) that runs in time linear in the number of job requests for the single vehicle scheduling problem on trees that have a constant number of leaves. This PTAS can be easily adapted to accommodate various starting/ending constraints. We then extended this to a PTAS for the multiple vehicle problem where vehicles operate in disjoint subtrees.