You may wish to apply the Levenstein's measure. The following link may of some help or provide some pointers. 

http://en.wikipedia.org/wiki/Levenshtein_distance

In general it is not possible to decide

whether two algorithms do the same,

see Rice's theorem.

http://en.wikipedia.org/wiki/Rice%27s_theorem

Regards,

Joachim

It looks a general question, 

But what i can recommend is to implement them both and use doxygen to visualize your codes and figure it out the differences between them.

You can find it in following link

http://www.stack.nl/~dimitri/doxygen/