Ok. Well for the rest: as you explore, you track the distance along edges that it took you to get to each node. For example, if we take a path to get to a node along an edge with distance 4 and an edge with distance 3, the distance would be 7. This is necessary to find the shortest path. So imagine we have two paths to a node. Along one path, the distance is 7. But say we come back later and the distance is only 4! If this is the case, we change the node's distance to 4 and readjust the parents. In this way, when we trace a path back, that path is always the shortest, because we explore all possible paths and always pick the shortest one we find.

Welcome!

This is the community forum for my apps Pythonista and Editorial.

For individual support questions, you can also send an email. If you have a very short question or just want to say hello — I'm @olemoritz on Twitter.