$20\mathrm{.}3-2$

Show how depth$-$rst search works on the graph of Figure $20\mathrm{.}6.$ Assume that the

for loop of lines $537$ of the DFS procedure considers the vertices in alphabetical

order, and assume that each adjacency list is ordered alphabetically. Show the

discovery and $$nish times for each vertex, and show the classi$$cation of each

edge.