We teach algorithmic topics at the University of Zurich on a regular basis.

Module | BMINF019 |

ECTS | 6 |

Instructor | Dr. Alexander Souza |

Contact | alexander@optineon.com |

Lecture Notes | here |

Exercise Sheets | here |

Introductory Slides | here |

Room | BIN-2.A.10 |

Weekdays | Tuesday 8:15-9:45 |

Thursday 8:15-9:45 | |

Exercises | biweekly, see schedule below |

Start | 19.2.2019 |

End | 28.5.2019 |

Exam | 11.6.2019 |

Admission | Half of the exercise problems must be worked on (serious attempt) for admission to the exam. |

UZH Link | here |

- We have a new room: BIN-2.A.10
- The exercise sheets are published
- NO CLASS on 2.5.; the class-schedule is updated
- Information on the Vertex Cover Challenge and grade improvement is available below
- Exercise 3 is postponed to 11.4. - Thus there is lecture on 4.4.
- Exercise 4 is postponed to 7.5. - This is a Tuesday
- Exercise 5 is postponed to 23.5.

This lecture covers central and classical results in the area of combinatorial optimization. In particular, the design and analysis of "combinatorial" as well as "approximation" algorithms are treated.

"Combinatorial algorithms" are exact and (mostly) polynomial-time methods, often based on dynamic programming, graphs, and linear programs.

"Approximation algorithms" produce (potentially sub-optimal) feasible solutions for (usually NP-hard) computational problems. The quality of these solutions is determined by comparison against an optimal solution.

The analysis will be an important and integral part. That is, we will not only state the properties of an algorithm, e.g. its correctness or running time, but also prove them mathematically.

In particular, we plan to treat the following topics:- Introduction
- Greedy Algorithms: Minimum Spanning Trees, Set Cover
- Network Flows: Maximum Flow, Minimum Cost Flow, Assignment
- Matchings: Blossom Algorithm
- Linear Programming: Polyhedra, Simplex
- Knapsack: Exact Algorithm, FPTAS
- Bin Packing: Hardness, Heuristics, APTAS
- Set Cover: Greedy, Primal-Dual, LP-Rounding
- Makespan Scheduling: Identical Machines, Unrelated Machines
- Satisfiability; LP-Rounding, Randimization, Derandomization

Tue 19.02.2019 | 8:15-9:45 | Introduction |

Thu 21.02.2019 | 8:15-9:45 | Greedy |

Tue 26.02.2019 | 8:15-9:45 | Greedy |

Thu 28.02.2019 | 8:15-9:45 | Greedy |

Tue 05.03.2019 | 8:15-9:45 | Network Flows |

Thu 07.03.2019 | 8:15-9:45 | Exercise 1 |

Tue 12.03.2019 | 8:15-9:45 | Network Flows |

Thu 14.03.2019 | 8:15-9:45 | Network Flows |

Tue 19.03.2019 | 8:15-9:45 | Matchings |

Thu 21.03.2019 | 8:15-9:45 | Exercise 2 |

Tue 26.03.2019 | 8:15-9:45 | Matchings |

Thu 28.03.2019 | 8:15-9:45 | Linear Programming |

Tue 02.04.2019 | 8:15-9:45 | Knapsack |

Thu 04.04.2019 | 8:15-9:45 | Knapsack |

Tue 09.04.2019 | 8:15-9:45 | Knapsack |

Thu 11.04.2019 | 8:15-9:45 | Exercise 3 |

Tue 16.04.2019 | 8:15-9:45 | Bin Packing |

Thu 18.04.2019 | 8:15-9:45 | Bin Packing |

Tue 30.04.2019 | 8:15-9:45 | Set Cover |

Thu 02.05.2019 | 8:15-9:45 | NO CLASS |

Tue 07.05.2019 | 8:15-9:45 | Exercise 4 |

Thu 09.05.2019 | 8:15-9:45 | Set Cover |

Tue 14.05.2019 | 8:15-9:45 | Makespan Scheduling |

Thu 16.05.2019 | 8:15-9:45 | Makespan Scheduling |

Tue 21.05.2019 | 8:15-9:45 | Satisfiability |

Thu 23.05.2019 | 8:15-9:45 | Exercise 5 |

Tue 28.05.2019 | 8:15-9:45 | Satisfiability |

Tue 11.06.2019 | 8:15-9:45 | Exam |

Given a graph G = (V, E), find a smallest subset C of V, such that each edge of E has at least one end-vertex in C.

This is a classical NP-hard optimization problem.

The organization PACE (Parameterized Algorithms and Computational Experiments) conducts an implementation and experimentation challenge for this problem.

Website: here

Instances: here

This offering is a bonus. It is possible to get a 6.0 for the course without participation in this challenge (by performance in the final exam). However, it is not possible to get a grade better than 6.0 in any case.

We have an online checker for evaluations of your solutions. Just enter your email and upload your solutions-file and receive a summary indicating instance, feasibility, and cover size. See here for an example submission. The input format is a csv-file with the rows: instance-name TAB v1 SPACE v2 SPACE ..., where v1, v2, denote the vertices of your solution for the respective instance.

- Cormen et al. – Introduction to Algorithms
- Korte, Vygen – Combinatorial Optimization
- Mitzenmacher, Upfal – Probability and Computing
- Vazirani – Approximation Algorithms

Scientific Contributions

We take part in scientific events and contribute actively to the operations research community. If you want to meet us, note the following meetings:

12-16.6.2017 | 13th MAPSP | Seon (Germany) |

6-7.2.2017 | Gurobi Days | Frankfurt (Germany) |

8.-12.6.2015 | 12th MAPSP | La Roche-en-Ardenne (Belgium) |

[S13] | Approximation Algorithms for Generalized Plant LocationMathematical Foundations of Computer Science (MFCS '13),
789 – 800, 2013 |

[HMS13] | A Simple and Tight Analysis for Generalized Vector
Packing joint work with Matthias Hellwig, Carsten Moldenhauer, submitted |

[AS13] | Buffer overflow management with class segregation joint with Kamal Al Bawani, Information Processing Letters, 113 (4), 145 – 150, 2013 |

[HS12] | Approximation Algorithms for Generalized and Variable
Sized Bin Covering joint with Matthias Hellwig, 15th International Workshop on Approximation Algorithms (APPROX ' 12), 194 – 205, 2012 |

[NS12] | Optimal Algorithms for Train Shunting and Relaxed List
Update Problems joint with Tim Nonner, 12th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS '12), 97 – 107, 2012 |

[S12] | Adversarial Models in Paging – Bridging the Gap between Theory and PracticeComputer Science - Research and Development, invited contribution, 27 (3), 197 – 205, 2012 |

[S12a] | Models and Algorithms for Assignment ProblemsHU Berlin, Habilitationsschrift, 2012 |

[A+11] | Balanced Interval Coloring joint with Antonios Antoniadis, Falk Hüffner, Pascal Lenzner, and Carsten Moldenhauer, 28th Symposium on Theoretical Aspects of Computer Science (STACS '11), 531 - 542, 2011 |

[LSS11] | Optimal File-Distribution in Heterogeneous and Asymmetric
Storage Networks joint with Tobias Langner and Christian Schindelhauer, 37th International Conference on Current Trends in Theory and Practice of Computer Science (SOFSEM '11), 368 - 381, 2011 |

[CNS10] | SRPT is 1.86-Competitive for Completion Time Scheduling joint with Christine Chung and Tim Nonner, 12th Symposium on Discrete Algorithms (SODA '10), 1373 - 1388, 2010 |

[HS10] | Tradeoffs and Average-Case Equilibria in Selfish Routing
joint with Martin Hoefer, journal version of [HS 07+08], Transactions on Computing Theory, 2 (1), 2010 |

[GNS09] | The Bell is Ringing in Speed-Scaled Multiprocessor
Scheduling joint with Gero Greiner and Tim Nonner, Symposium on Parallelism in Algorithms and Architectures (SPAA '09), 11-18, 2009 |

[AS09] | Competitive Buffer Management with Stochastic Packet
Arrivals joint with Kamal Al-Bawani, 8th Symposium on Experimental Algorithms (SEA '09), 28 - 40, 2009 |

[NS09a] | A 5/3-approximation algorithm for joint replenishment
with deadlines joint with Tim Nonner, 3rd Conference on Combinatorial Optimization and Applications (COCOA '09), 24 - 35, 2009 |

[NS09] | Latency Constrained Data Aggregation in Chain Networks joint with Tim Nonner, 5th Conference on Algorithmic Aspects in Information and Management (AAIM '09), 279 - 291, 2009 |

[SS09] | On an Online Traveling Repairman Problem with Flowtimes:
Worst-Case and Average-Case Analysis joint with Axel Simroth, 15th International Computing and Combinatorics Conference (COCOON '09), 168 - 177, 2009 |

[HS08] | The Influence of Link Restrictions in (Random) Selfish
Routing joint with Martin Hoefer, 1st Symposium on Algorithmic Game Theory (SAGT '08), 22 - 32, 2008 |

[HS07] | Tradeoffs and Average-Case Equilibria in Selfish Routing joint with Martin Hoefer, 15th European Symposium on Algorithms (ESA '07), 63 - 74, 2007 |

[RSS07] | On an Online Spanning Tree Problem in Randomly Weighted
Graphs joint with Jan Remy and Angelika Steger, Combinatorics, Probability and Computing, 16, 127 - 144, 2007 |

[S06] | Average Performance AnalysisETH Zurich, Doctoral Thesis, 2006 |

[PS06] | On Adequate Performance Measures for Paging joint with Konstantinos Panagiotou, 38th ACM Symposium on Theory of Computing (STOC '06), 487 - 496, 2006 |

[SS06] | The Expected Competitive Ratio for Weighted Completion
Time Scheduling joint with Angelika Steger, journal version of [SS04], invited contribution, Theory of Computing Systems, 39:1, 2006, pages 121 - 136 |

[SS04] | The Expected Competitive Ratio for Weighted Completion
Time Scheduling joint with Angelika Steger, 21th Symposium on Theoretical Aspects of Computer Science (STACS ' 04), LNCS 2996, pages 620 - 631, Springer Verlag |

[S01] | Algorithms for Channel Assignment TU Munich, Diploma Thesis, 2001 |