Amortized efficiency of list update and paging rules
Communications of the ACM
Theoretical Computer Science
The Canadian Traveller Problem
SODA '91 Proceedings of the second annual ACM-SIAM symposium on Discrete algorithms
Online computation and competitive analysis
Online computation and competitive analysis
A Risk-Reward Competitive Analysis for the Recoverable Canadian Traveller Problem
COCOA 2008 Proceedings of the 2nd international conference on Combinatorial Optimization and Applications
The k-canadian travelers problem with communication
FAW-AAIM'11 Proceedings of the 5th joint international frontiers in algorithmics, and 7th international conference on Algorithmic aspects in information and management
The k-Canadian Travelers Problem with communication
Journal of Combinatorial Optimization
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We consider the online problem k-CTP, which is the problem to guide a vehicle from some site s to some site t on a road map given by a graph G=(V,E) in which up to k (unknown) edges are blocked by avalanches. An online algorithm learns from a blocked edge when reaching one of its endpoints. Thus, it might have to change its route to the target t up to k times. We show that no deterministic online algorithm can achieve a competitive ratio smaller than 2k+1 and give an easy algorithm which matches this lower bound. Furthermore, we show that randomization can not improve the competitive ratio substantially, by establishing a lower bound of k+1 for the competitivity of randomized online algorithms against an oblivious adversary.