Recursive DFS on an undirected graph from a start vertex. Reads the Algs4 Graph format (V, then E, then the edges). Watch the stack grow as Theseus's thread, and the adjacency-list iterators advance.
Graph): first line is the number of vertices V,
second line is the number of edges E, then E lines each holding an
undirected edge v w. Vertices are 0 … V−1. Parallel edges and self-loops
are allowed. Adjacency lists are built by prepending (a Sedgewick Bag), so a vertex's
neighbours appear in reverse order of how the edges were read — matching the booksite traversal order.
V more lines of
x y — one pair per vertex, in order — to pin down your own layout instead of the
automatic one. Any numeric scale works; it's auto-centred and scaled to fit, preserving relative
position and aspect ratio. Loading a graph always fills the box back in with its current layout's
coordinates so you can nudge them; tick the box above to see the plain format instead.