Hmm. I imagine that determining which intervals can be picked to make a continuous span is really a graph-traversal algorithm. However you aren't just given al

Hmm. I imagine that determining which intervals can be picked to make a continuous span is really a graph-traversal algorithm. However you aren't just given all the existing edges (pair overlaps) in advance, maybe there's a way to have the graph-exploration side guide the edge-detection to minimize work.