A process determines for a search string which, if any, of the strings in a text list have edit distance from the search string less than a threshold. The process uses dynamic programming on a grid with search string characters corresponding to rows and text characters corresponding to columns. For each text string, computation proceeds by columns. If successive text strings share a prefix, then the columns corresponding to the prefix are re-used. If the minimum value in a column is at least the threshold, then the prefix corresponding to that and previous columns causes edit distance to be at least the threshold. So the computation for the present text is abandoned, and computations for any other texts that share the prefix are avoided.