Note: This is almost the same questions as this: [Shortest path to visit all nodes](https://stackoverflow.com/questions/33583392/shortest-path-to-visit-all-nodes)

**But I have a complete graph.** 

Problem: Consider a complete undirected graph with nonnegative edge lengths. Question: Compute the shortest path that visits every node **at least once**. 

***NB:*** This is NOT the TSP problem. The path does not have an ending node and the path can pass through nodes more than once. 

**Other notes:** 

The number of nodes is small (less than 20).