Intuitively, it should be easiest to find the shortest path to nearby destinations. “The authors were audacious in thinking they could break this barrier,” said Robert Tarjan, a computer scientist at Princeton University. Given a graph and a specific “source” node, an algorithm’s goal is to find the shortest path to every other node. The most famous shortest-paths algorithm, devised by the pioneering computer scientist Edsger Dijkstra in 1956, starts at the source and works outward step by step. It’s an effective approach, because knowing the shortest path to nearby nodes can help you find the shortest paths to more distant ones.