Chierichetti_etal2008
Proceedings
Acm
2008
Web Search and Web Data Mining (WSDM 2008)
15-24
ChierichettiFlavio
LattanziSilvio
MariFederico
PanconesiAlessandro
NajorkM.
BroderA.Z.
ChakrabartiS.
On Placing Skips Optimally in Expectation
We study the problem of optimal skip placement in an inverted list. Assuming the query distribution to be known in advance, we formally prove that an optimal skip placement can be computed quite efficiently. Our best algorithm runs in time O(n log n), n being the length of the list. The placement is optimal in the sense that it minimizes the expected time to process a query. Our theoretical results are matched by experiments with a real corpus, showing that substantial savings can be obtained with respect to the tra- ditional skip placement strategy, that of placing consecutive skips, each spanning sqrt(n) many locations.