Russell Eveleigh is using a Raspberry Pi Pico to demonstrate Dijkstra's algorithm visually with LEDs arranged as a map of the Cotswolds in England.

In one specific sense, this version of Dijkstra’s algorithm is the best possible. That was the last word on the standard version of the problem for nearly 40 years.

For decades, computer scientists working on negative-weight graphs tried to match the speed of Dijkstra’s algorithm with similar “combinatorial” algorithms. These involve discrete operations — like ...