two questions about unicyclic graph

From: Joe (Joe.ntang_at_gmail.com)
Date: 01/17/05 

Date: 17 Jan 2005 06:56:11 -0800

Hello,

I have two problems when dealing with unicyclic graph:

1. a linear algorithm to find the centre of a unicyclic graph
2. a linear algorithm to judge whether two unicyclic graphs are
isomorphic

I have thought about it for several days but cannot get a good answer,
so anybody could give me some hint or help ?