Graphs (directed)
Graphs (directed)
Graphs (directed) class work
Logistics
New pods!
Status flags
Each team has a status flag that you can use to help me focus where to go:
green: working, no questions
yellow: have a question, but not blocked from doing work
red: have a question, blocked from doing work
blue: done, just hanging out
Articulation practice
Remember: this is an opportunity to practice clear, concise and precise communication while working through the material!
Throughout the course, each of you must volunteer at least once to serve as the facilitator, who will:
Make sure everyone has a chance for their voice to be heard. For example, saying:
“X, we haven’t heard from you in a while. Do you have thoughts on this problem or is there another one you’d like to shift to?”Keep track of time to cover as much of each problem as possible
Post a clearly articulated report with a summary and/or questions to the corresponding Ed Discussion category
Please be sure to also post your pod # and other team members, as in “Report for Pod 2 (Audrey St. John, Mary Lyon, …)”
If you’d prefer to use a doc, post the link or turn it into an image to attach
If you have work from the board, you can take a photo and post it
Directed BFS/DFS
At the board, each group will:
Draw a connected directed graph with at least 6 vertices that is not a tree.
Rotate clockwise.
Perform a BFS from vertex C or 3 (depending on labels) and draw the tree and dotted non-tree edges.
Rotate clockwise.
Perform a DFS from vertex C or 3 (depending on labels) and draw the tree and dotted non-tree edges.
Topological orderings
Below is a list of edges in a directed graph with nodes A, B, C, D, E, and F.
B → E, B → F, C → D, D → A, E → F.
Find five topological ordering of the graph above.
Say that you want the ordering ABCDEF to be a topological ordering. Which edge must be removed to do this?
Say that you didn’t want any topological orderings to be possible. What is an edge you could add that would achieve this effect?
Say that the only nodes in the graph were B, E, and F. How many topological orderings are possible here?