Variable sized online interval coloring with bandwidth

Leah Epstein, Thomas Erlebach, Asaf Levin

Research output: Contribution to journalArticlepeer-review


We consider online coloring of intervals with bandwidth in a setting where colors have variable capacities. Whenever the algorithm opens a new color, it must choose the capacity for that color and cannot change it later. A set of intervals can be assigned the same color a of capacity C a if the sum of bandwidths of intervals at each point does not exceed C a. The goal is to minimize the total capacity of all the colors used. We consider the bounded model, where all capacities must be chosen in the range (0,1], and the unbounded model, where the algorithm may use colors of any positive capacity. For the absolute competitive ratio, we give an upper bound of 14 and a lower bound of 4.59 for the bounded model, and an upper bound of 4 and a matching lower bound of 4 for the unbounded model. We also consider the offline version of these problems and show that whereas the unbounded model is polynomially solvable, the bounded model is NP-hard in the strong sense and admits a 3.6-approximation algorithm.

Original languageEnglish
Pages (from-to)385-401
Number of pages17
Issue number3
StatePublished - Mar 2009


  • Approximation algorithm
  • Competitive analysis
  • Interval coloring
  • Lower bound

ASJC Scopus subject areas

  • General Computer Science
  • Computer Science Applications
  • Applied Mathematics


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