# Max-weight path of fixed length?

I have a problem which I've reduced down to the following requirements:

Given an:

• undirected graph $G$ that may contain cycles, with positive weighted nodes and edges of length $1$,
• a subset of nodes $M$,
• a length $L$,

return the path of maximum weight (calculated by summing up the weights of its nodes) that contains all nodes in $M$ and is exactly length $L$.

(A more complex requirement that I'm omitting is that including certain nodes in the path may increase the values of other nodes.)

I'm just looking for a nod in the right direction - are there any algorithms or terms that might be relevant to this situation?

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If $L+1$ happens to be the number of nodes in the graph and the path is required to be simple, this becomes the Hamiltonian path problem... –  Rahul Jan 27 '13 at 1:00