Efficient Graph Search
Terence Kelly · Queue · 2020
Welcome to Drill Bits , a new column about programming. This inaugural episode shows how graph search algorithms can avoid unnecessary work. A simple modification to classic breadth-first search improves the lower bound on its running time: Whereas classic BFS always requires time proportional to the number of vertices plus the number of edges, the improved "Efficient BFS" sometimes runs in time proportional to the number of vertices alone. Both asymptotic analysis and experiments show that Efficient BFS can be much faster than classic BFS. All software used in the experiments is available for download, and suggestions for further explorations are provided.