Algorithm for finding circular references in a spreadsheet

Question

I have a spreadsheet application with formulas. I am looking for the best algorithm for detecting circular references among the formulas. The current approach I have is slow and

Answer 1

You need to do a topological sorting of the cells anyway in order to be able to rapidly calculate the values of cells when something is changed. The topological sorting procedure also detect cycles as a byproduct.

See http://en.wikipedia.org/wiki/Topological_sorting