POJ 3592 - Instaneous Transference
Problem : Given a graph, find a path from given source to destination, such that the sum of passed vertices' value is maximum. (The value is always non-negative).
Solution : The value of strong-connected set can always get all, thus merge them into single vertices. Then the graph become DAG. Then do the topological DP on the DAG can get the answer. Be careful that all the vertices should be considered in the topological pick. And the current optimum sum of vertices which doesn't come from source should always be negative(WA is gotten here, that not all the vertices is considered).