2009/06/07 by Emanuele Viola, Viola, Emanuele
Computer Science · #Computational Complexity (cs.CC) #Data Structures and Algorithms (cs.DS) #FOS: Computer and information sciences #cs.CC #cs.DS
paper · pdf · doi:10.48550/arxiv.0906.1370
arxiv created 2009/06/07 · arxiv updated 2009/12/01
We prove that to store n bits x so that each prefix-sum query Sum(i) := sumk < i xk can be answered by non-adaptively probing q cells of log n bits, one needs memory > n + n/logO(q) n. Our bound matches a recent upper bound of n + n/logOmega(q) n by Patrascu (FOCS 2008), also non-adaptive. We also obtain a n + n/log^2O(q) n lower bound for storing a string of balanced brackets so that each Match(i) query can be answered by non-adaptively probing q cells. To obtain these bounds we show that a too efficient data structure allows us to break the correlations between query answers.