What is dynamic programming algorithm for finding a Hamiltonian cycle in an undirected graph?
I have seen somewhere that there exists an algorithm with O(n.2^n)
I can't pluck out that particular algorithm, but there is more about Hamiltonian Cycles on The Hamiltonian Page than you will likely ever need. :)
This page intends to be a comprehensive listing of papers, source code, preprints, technical reports, etc, available on the Internet about the Hamiltonian Cycle and Hamiltonian Path Problems as well as some associated problems.
(original URL, currently 404), (Internet Archive)