Linear-time triangulation of a simple polygon made easier via randomization

Nancy M. Amato, Michael T. Goodrich, Edgar A. Ramos

Research output: Contribution to conferencePaperpeer-review


We describe a randomized algorithm for computing the trapezoidal decomposition of a simple polygon. Its expected running time is linear in the size of the polygon. By a well-known and simple linear time reduction, this implies a linear time algorithm for triangulating a simple polygon. Our algorithm is considerably simpler than Chazelle's (1991) celebrated optimal deterministic algorithm and, hence, positively answers his question of whether a simpler randomized algorithm for the problem exists. The new algorithm can be viewed as a combination of Chazelle's algorithm and of non-optimal randomized algorithms due to Clarkson et al. (1991) and to Seidel (1991), with the essential innovation that sampling is performed on subchains of the initial polygonal chain, rather than on its edges. It is also essential, as in Chazelle's algorithm, to include a bottom-up preprocessing phase previous to the top-down construction phase.

Original languageEnglish (US)
Number of pages12
StatePublished - 2000
Externally publishedYes
Event16th Annual Symposium on Computational Geometry - Hong Kong, Hong Kong
Duration: Jun 12 2000Jun 14 2000


Other16th Annual Symposium on Computational Geometry
CityHong Kong, Hong Kong

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Geometry and Topology
  • Computational Mathematics


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