Computer Science 163/265, Spring 2018:
Graph Algorithms

General Course Information

The course meets Monday, Wednesday, and Fridays, 3:00 - 3:50 in Bren Hall, room 1100. Prof. Eppstein's office hours are Mondays and Wednesdays from 4:00 - 5:00 (or by appointment) in Bren 4082. The teaching assistants are Nil Mamano (, office hours Wed 2-3, Fri 2-3 and 4-5 in DBH 4061) and Elham Havvaei (, office hours Mon 2-3 and Tue 3-5 in DBH 4061). We also have a reader, Kanika Baijal. After the lectures, the lecture slides will be available for viewing at the TA office hours.

Coursework will consist of weekly homeworks, a midterm, and a comprehensive final exam. Group work on homeworks is permitted; each student should turn in his or her own copy of the homeworks. The undergraduate (163) and graduate (265) courses will share lectures, and some homework problems; however, the graduate course will have additional homework problems and different exams. Homeworks will typically be assigned on Fridays and due on the following Friday, electronically in PDF format using gradescope (check your course emails or the course forum on Piazza for details).

The text we will be using is Graph Algorithms, a collection of readings compiled from Wikipedia. Lecture materials will not be distributed to the class; instead, you are encouraged to attend the lecture yourself and take your own notes. Recording the lectures for your own personal use is allowed, but other uses of recorded lectures (including making them available online) is forbidden.

The final grade will be formed by combining the numerical scores from the homeworks (20%), midterm (35%), and final (45%).

Tentative Schedule of Topics

Week 1.
Web crawler case study. PageRank algorithm. DFS, BFS, Tarjan's algorithm for strongly connected components. Representation of graphs.
Homework 1, due Friday, April 13. To start working from this template, click "clone this project", and then when your answers are complete, download your copy by clicking "pdf". However, you are not required to use this template for your answers. After the deadline, the same link will be updated with the solutions.
Week 2.
Maze and river network simulation via invasion percolation case study. Minimum spanning trees, Prim-Dijkstra-Jarnik algorithm, Boruvka's algorithm, Kruskal's algorithm.
Spreadsheet case study. DAGs and topological ordering.
Homework 2, due Friday, April 20.
Week 3.
Road map path planning case study. Shortest paths, relaxation algorithms, Dijkstra's algorithm, Bellman-Ford algorithm, Johnson's algorithm.
A* algorithm.
Homework 3, due Friday, April 27.
Week 4.
Preference voting case study and the widest path problem.
Guest lecture Wednesday, April 25: Euler tours.
Transportation scheduling case study. Travelling salesman problem.
Exponential-time dynamic programming for the TSP.
Homework 4, due Friday, May 4.
Week 5.
Approximation algorithms and the approximation ratio, MST-doubling heuristic, Christofides' heuristic.
Review session Wednesday, May 2.
Midterm Friday, May 4.
Week 6.
Baseball elimination case study. Maximum flow problem, minimum cut problem, max-flow min-cut theorem, augmenting path (Ford-Fulkerson) algorithm.
Homework 5, due Friday, May 18.
Week 7.
Medical school residency assignment case study. Matchings, stable marriage, Gale-Shapley algorithm for stable marriage.
Bipartite graphs, formulating bipartite maximum matching as a flow problem, Hopcroft–Karp algorithm.
Using matchings to find vertex covers and independent sets, partition into a minimum number of rectangles.
Homework 6, due Friday, May 25.
Week 8.
Register allocation case study. Strahler number, graph coloring, greedy coloring, interval graphs, and perfect graphs.
Chordal graphs and using Lexicographic breadth-first search to find an elimination ordering.
Homework 7, due Friday, June 1.
Week 9.
Memorial day holiday, Monday, May 28.
Social network analysis case study. Social network properties: sparsity, small world property, power laws. Barabási-Albert model, degeneracy and k-cores.
Cliques, Moon-Moser bound on maximal cliques, Bron-Kerbosch algorithm.
Homework 8, due Friday, June 8.
Week 10.
Planar graphs; review of planarity-related topics from earlier weeks (graph drawing, road maps, invasion percolation via minimum spanning trees of grid graphs, graph coloring and the four-color theorem).
Duality, duality of Euler tours and bipartiteness, Euler's formula, greedy 6-coloring, Boruvka in linear time. Planarity testing, and Fáry's theorem.
Finals week
Final examination (cumulative), Mon, June 11, 4:00-6:00pm.

Material from Previous Course Offerings

The syllabus from Spring 2015 has more links, to syllabi and exams from earlier quarters.