Two Algorithms for Finding $k$ Shortest Paths of a Weighted Pushdown   Automaton
  We introduce efficient algorithms for finding the $k$ shortest paths of a weighted pushdown automaton (WPDA), a compact representation of a weighted set of strings with potential applications in parsing and machine translation. Both of our algorithms are derived from the same weighted deductive logic description of the execution of a WPDA using different search strategies. Experimental results show our Algorithm 2 adds very little overhead vs. the single shortest path algorithm, even with a large $k$. 
Ke Wu, Philip Resnik
cs.CL cs.DS cs.FL