Lecture 17

CSE 331Oct 7, 2011

HW 4 due today

Q1, Q2 and Q3 in separate piles

I will not take any HW after 1:15pm

Mid term

Monday in class at 1pm

Unfortunately I won’t be there

Jiun-Jie with my PhD students Steve & Swapnoneel will proctor the exam

Graded HW 3 & solutions to HW4

Graded HW3 in office-hour-a-thon

Solutions to HW 4 at the end of the lecture

On Friday, Oct 7

hours-a-thon

Atri: 2:00-3:00 (Bell 123)

Jiun-Jie: 4:00-5:00 (Commons 9)Jesse: 5:00-6:00 (Bell 224)

UnclaimedHWs and solutions

UnclaimedHWs and solutions

To form a group

Can use comment section on the blog

(Do not use the anonymous comment link)

If there is interest

Can spend last 10 mins taking questions on the mid-term

Directed graphs

Model asymmetric relationships

Precedence relationships

u needs to be done before v means (u,v) edge

Directed graphsAdjacency

matrix is not symmetric

Adjacency matrix is not symmetric

Each vertex has two lists in Adj. list rep.

Each vertex has two lists in Adj. list rep.

Directed Acyclic Graph (DAG)

No directed cycles

Precedence relationships are

consistent

Precedence relationships are

consistent

Topological Sorting of a DAG

Order the vertices so that all edges go “forward”

Topological sorting DAG

Topological sorting DAG

HW 4 due today

Q1, Q2 and Q3 in separate piles

I will not take any HW after 1:15pm

Today’s agenda

DAG topological sorting

A notation announcement

I will (try to) not use u from now on

Run of TopOrd algorithm