\input zb-basic \input zb-ioport \iteman{io-port 06064143} \itemau{Becher, Ver\'onica; Heiber, Pablo Ariel} \itemti{A linearly computable measure of string complexity.} \itemso{Theor. Comput. Sci. 438, 62-73 (2012).} \itemab Summary: We present a measure of string complexity, called I-complexity, computable in linear time and space. It counts the number of different substrings in a given string. The least complex strings are the runs of a single symbol, the most complex are the de Bruijn strings. Although the I-complexity of a string is not the length of any minimal description of the string, it satisfies many basic properties of classical description complexity. In particular, the number of strings with I-complexity up to a given value is bounded, and most strings of each length have high I-complexity. \itemrv{~} \itemcc{} \itemut{} \itemli{doi:10.1016/j.tcs.2012.03.007} \end