1. Lecture 38 CSE 331 Dec 7, 2009

2. The last few days Today: Solutions to HW 9 (end of lecture) Wednesday: Graded HW 9 (?), Sample final, Blog post on the final exam Friday: HW 10 due, solutions to HW 10 out, last lecture Monday (Dec 14): Review session, solutions to sample final Wednesday (Dec 16): Final exam Friday (Dec 18): Graded Finals and HW 10

3. When to use Dynamic Programming There are polynomially many sub-problems Optimal solution can be computed from solutions to sub-problems There is an ordering among sub-problem that allows for iterative solution Richard Bellman

4. Shortest Path Problem Input: (Directed) Graph G=(V,E) and for every edge e has a cost c e (can be <0) t in V Output: Shortest path from every s to t 1 1 100 -1000 899 s t Shortest path has cost negative infinity Assume that G has no negative cycle

5. Today’s agenda Dynamic Program for shortest path Group talk time: Come up with a recursion Group talk time: Come up with a recursion

6. May the Bellman force be with you