human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "the packing while traveling problem"
  Abstract: This paper introduces the Packing While Traveling problem as a new non-linear knapsack problem. Given are a set of cities that have a set of items of distinct profits and weights and a vehicle that may collect the items when visiting all the cities in a fixed order. Each selected item contributes its profit, but produces a transportation cost relative to its weight. The problem asks to find a subset of the items such that the total gain is maximized. We investigate constrained and unconstrained versions of the problem and show that both are NP-hard. We propose a pre-processing scheme that decreases the size of instances making them easier for computation. We provide lower and upper bounds based on mixed-integer programming (MIP) adopting the ideas of piecewise linear approximation. Furthermore, we introduce two exact approaches: one is based on MIP employing linearization technique, and another is a branch-infer-and-bound (BIB) hybrid approach that compounds the upper bound procedure with a constraint programming model strengthened with customized constraints. Our experimental results show the effectiveness of our exact and approximate solutions in terms of solution quality and computational time.

Connected through hyperedge HE-1 (induced by source paper "dynamic multi objective optimization of the travelling thief problem"):
  with members:
    - "exact approaches for the travelling thief problem"

Connected through hyperedge HE-2 (induced by source paper "analysis of baseline evolutionary algorithms for the packing while travelling problem"):
  with members:
    - "precise runtime analysis for plateaus"
    - "a fully polynomial time approximation scheme for packing while traveling"
    - "evolutionary computation for multicomponent problems opportunities and future directions"
    - "packing while traveling mixed integer programming for a class of nonlinear knapsack problems"

Connected through hyperedge HE-3 (induced by source paper "evolutionary computation plus dynamic programming for the bi objective travelling thief problem"):
  with members:
    - "exact approaches for the travelling thief problem"
    - "a fully polynomial time approximation scheme for packing while traveling"
    - "a case study of algorithm selection for the traveling thief problem"

Connected through hyperedge HE-4 (induced by source paper "exact approaches for the travelling thief problem"):
  with members:
    - "a fully polynomial time approximation scheme for packing while traveling"
    - "a case study of algorithm selection for the traveling thief problem"
    - "cosolver2b an efficient local search heuristic for the travelling thief problem"

Connected through hyperedge HE-5 (induced by source paper "a fully polynomial time approximation scheme for packing while traveling"):
  with members:
    - "approximation algorithms for route planning with nonlinear objectives"
    - "packing while traveling mixed integer programming for a class of nonlinear knapsack problems"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.DS(Data Structures and Algorithms)