[evah]

This was the day 25 problem: given a graph of ~1600 nodes and ~3500 edges, find the 3 edges that if deleted divide the graph into 2 components. I looked over some of the solutions and it surprised me how few used the simplest method: for each edge with endpoints u, v in the graph, delete it and then find another path P1 between u and v. Then, for each edge e1 in P1, delete it and then find another path P2 between u and v. Then, for each edge e2 in P2, delete it and then try to find another path between u and v. If there is no path, (u, v), e1, e2 is your cut-set. Otherwise, add e2 back and try the next edge in P2. When you've exhausted P2, add e1 back and try the next edge in P1. When you've exhausted P1, add (u, v) back and try the next edge in the graph. It's 3-6 loops deep depending on how you count, but it works. My python implementation completes in under 2 minutes, but it varies because it appears the standard python data structures have some nondeterminism, and I may have had a lucky draw with my puzzle input.