This book constitutes the refereed proceedings of the 5th Italian Conference on Algorithms and Computation, CIAC 2003, held in Rome, Italy in May 2003. The 23 revised full papers presented were carefully reviewed and selected from 57 submissions. Among the topics addressed are complexity, complexity theory, geometric computing, matching, online algorithms, combinatorial optimization, computational graph theory, approximation algorithms, network algorithms, routing, and scheduling.

The papers in this volume were presented at the Fourth Italian Conference on Algorithms and Complexity (CIAC 2000). The conference took place on March 1-3, 2000, in Rome (Italy), at the conference center of the University of Rome \La Sapienza." This conference was born in 1990 as a national meeting to be held every three years for Italian researchers in algorithms, data structures, complexity, and parallel and distributed computing. Due to a signi cant participation of foreign reaserchers, starting from the second conference, CIAC evolved into an international conference. In response to the call for papers for CIAC 2000, there were 41 subm- sions, from which the program committee selected 21 papers for presentation at the conference. Each paper was evaluated by at least three program committee members. In addition to the selected papers, the organizing committee invited Giorgio Ausiello, Narsingh Deo, Walter Ruzzo, and Shmuel Zaks to give plenary lectures at the conference. We wish to express our appreciation to all the authors of the submitted papers, to the program committee members and the referees, to the organizing committee, and to the plenary lecturers who accepted our invitation.