An approximation algorithm for the shortest cycle in an undirected unweighted graph

This paper improves Itai and Rodeh´s algorithm for finding a shortest cycle in an undirected unweighted graph. Given an undirected unweighted graph G with n vertices,the algorithm can determine a cycle whose length is at most k+1 where k is the length of the shortest cycle in G. The results of the experiment show that the improved algorithm runs faster than the original one when the input graph meets some special features.