Before revision:  R-index Gagie et al., ACM'20 is an efficient compressed index on RLBWTwhose space usage depends not on string length but the number of runs in an RLBWT, and it supports locate queries in an optimal time with \omega are two key functions for building indexes on RLBWT, and the best previous result computes LF and \phi^{-1} in O(\log \log n) time with O} (r) words for the number r of runs in the RLBWTof an input string. Following this line of research, we present the first compressed index on RLBWT, which we callr-index-f , that supports various queries including locate, count, extract queries, decompression and prefix search in the optimal time with smaller working space of O(r) words for small alphabets in this paper.
After revision:  R-index Gagie et al., ACM'20 is an efficient compressed index on RLBWTwhose space usage depends not on string length but the number of runs in an RLBWT, and it supports locate queries in an optimal time with \omega are two key functions for building indexes on RLBWT, and the best previous result computes LF and \phi^{-1} in O(\log \log n) time with O} (r) words for the number r of runs in r-index-f , that supports various queries including locate, count, extract queries, decompression and prefix search in the optimal time with smaller working space of O(r) words for small alphabets in this paper.