The online Prize-Collecting Traveling Salesman Problem

  • Authors:
  • Giorgio Ausiello;Vincenzo Bonifaci;Luigi Laura

  • Affiliations:
  • Dipartimento di Informatica e Sistemistica, Sapienza Università di Roma, Via Ariosto 25, 00185 Roma, Italy;Dipartimento di Informatica e Sistemistica, Sapienza Università di Roma, Via Ariosto 25, 00185 Roma, Italy and Dipartimento di Ingegneria Elettrica, Università dell'Aquila, Monteluco di ...;Dipartimento di Informatica e Sistemistica, Sapienza Università di Roma, Via Ariosto 25, 00185 Roma, Italy

  • Venue:
  • Information Processing Letters
  • Year:
  • 2008

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Abstract

We study the online version of the Prize-Collecting Traveling Salesman Problem (PCTSP), a generalization of the Traveling Salesman Problem (TSP). In the TSP, the salesman has to visit a set of cities while minimizing the length of the overall tour. In the PCTSP, each city has a given weight and penalty, and the goal is to collect a given quota of the weights of the cities while minimizing the length of the tour plus the penalties of the cities not in the tour. In the online version, cities are disclosed over time. We give a 7/3-competitive algorithm for the problem, which compares with a lower bound of 2 on the competitive ratio of any deterministic algorithm. We also show how our approach can be combined with an approximation algorithm in order to obtain an O(1)-competitive algorithm that runs in polynomial time.