Improved Range Minimum Queries
Héctor Ferrada and Gonzalo Navarro
Fischer and Heun [SICOMP 2011] proposed the first Range Minimum Query (RMQ)
data structure on an array A[1,n] that uses 2n+o(n) bits and answers
queries in O(1) time without accessing A. Their scheme converts the
Cartesian tree of A into a general tree, which is represented using DFUDS.
We show that, by using instead the BP representation, the formula becomes
simpler since border conditions are eliminated. We also improve the current
implementation of the BP representation for this purpose. This leads to the
fastest and most compact practical implementation to date.