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: "space time tradeoffs for subset sum an improved worst case algorithm"
  Abstract: The technique of Schroeppel and Shamir (SICOMP, 1981) has long been the most efficient way to trade space against time for the SUBSET SUM problem. In the random-instance setting, however, improved tradeoffs exist. In particular, the recently discovered dissection method of Dinur et al. (CRYPTO 2012) yields a significantly improved space--time tradeoff curve for instances with strong randomness properties. Our main result is that these strong randomness assumptions can be removed, obtaining the same space--time tradeoffs in the worst case. We also show that for small space usage the dissection algorithm can be almost fully parallelized. Our strategy for dealing with arbitrary instances is to instead inject the randomness into the dissection process itself by working over a carefully selected but random composite modulus, and to introduce explicit space--time controls into the algorithm by means of a "bailout mechanism".

Connected through hyperedge HE-1 (induced by source paper "equal subset sum faster than the meet in the middle"):
  with members:
    - "ppp completeness with connections to cryptography"
    - "a simple near linear pseudopolynomial time randomized algorithm for subset sum"
    - "subset sum made simple"
    - "seth based lower bounds for subset sum and bicriteria path"
    - "on problems as hard as cnf sat"
    - "a near linear pseudopolynomial time algorithm for subset sum"
    - "number balancing is as hard as minkowski s theorem and shortest vector"
    - "a faster pseudopolynomial time algorithm for subset sum"

Connected through hyperedge HE-2 (induced by source paper "on space efficiency of algorithms working on structural decompositions of graphs"):
  with members:
    - "an o n epsilon space and polynomial time algorithm for reachability in directed layered planar graphs"
    - "space saving by dynamic algebraization"
    - "one hierarchy spawns another graph deconstructions and the complexity classification of conjunctive queries"
    - "where first order and monadic second order logic coincide"
    - "narrow sieves for parameterized paths and packings"
    - "model checking problems as a basis for parameterized intractability"

Connected through hyperedge HE-3 (induced by source paper "a faster pseudopolynomial time algorithm for subset sum"):
  with members:
    - "a near linear pseudopolynomial time algorithm for subset sum"
    - "clustered integer 3sum via additive combinatorics"
    - "optimal rectangle packing an absolute placement approach"
    - "covering sets for limited magnitude errors"

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)