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CS614 | Jan-Apr 2025

CS614. Advanced Algorithms

Jan-Apr 2025

(co-instructor with Prof. Manoj Gupta.)

This website pertains to the first half of the course. A link to the second half will be available here soon.

About the Course

This course will explores the tradeoffs involved in coping with NP-completeness.

When we think about designing algorithms, we are usually very demanding in how we go about it: we require our algorithms to be fast and accurate on all conceivable inputs. This is asking for quite a bit, and perhaps it is not surprising that we cannot afford this luxury all the time. The good news is that most of the time we can make meaningful progress by relaxing just one of these demands:

  1. Give up on accuracy, but not completely: look for solutions that are good enough (approximation) and/or work with algorithms that report the right solution most of the time (Las-Vegas style randomization).

  2. Give up on coverage, a little bit: let your algorithms work well on structured inputs. Hopefully the structure is such that it is not too limiting and is interesting enough for some application scenario, and is also enough to give you algorithmic leverage, i.e, there’s enough that you can exploit to make fast and accurate algorithms.

  3. Give up on speed, to some extent: going beyond the traditional allowance of polynomial time, which is the holy grail of what is considered efficient, takes you places. You could either allow for your algorithms have super-polynomial running times, and optimize as much as possible while being accurate on all inputs (exact algorithms), or allow for bad running times on a bounded subset of instances (Monte-Carlo style randomization).

This first half of this course will focus on techniques in approximation algorithms, where we mostly focus on getting near-optimal solutions in polynomial time, with varying degrees of closeness to OPT. In the second half, we will learn about randomized algorithms.

Overview of tradeoffs
Target Audience

Anyone who is biting their nails from the NP-completeness cliffhanger at the end of their introduction to algorithms will probably enjoy this course.

Prerequisites

This is a theoretical course that will require mathematical maturity (in particular, the ability to understand and write formal mathematical proofs), and some background in the design and analysis of algorithms. Programming experience is tangentially useful but not necessary. For students of IITGN, this course naturally follows up on DSA-II.

References
  1. The Design of Approximation Algorithms • David P. Williamson and David B. Shmoys
  2. Parameterized Algorithms • Marek Cygan, Fedor V. Fomin, Lukasz Kowalik, Daniel Lokshtanov, Daniel Marx, Marcin Pilipczuk, Michal Pilipczuk, and Saket Saurabh
  3. Randomized Algorithms • Motwani and Raghavan
  4. Beyond the Worst-Case Analysis of Algorithms • Tim Roughgarden
  5. Algorithms • Jeff Erickson
Timings and Venue
  • Lectures on Mondays and Thursdays: 11.30AM — 1PM (11/206)
  • Office Hours: By email.
Register
  • Register through IMS
  • Assessments on Gradescope (Code: 3RVXNG)
  • Announcements on Google Classroom (Code: qrquvxi)
Evaluation policy

Grading (First Half - 50%): 12 Worksheets (40%) + Take-Home Exam (10%)

Note: the videos here are unedited livestream recordings, mostly shared here for the record: pursue them at your own risk. Apologies for the choppy audio in a few of them!

Date Lecture Slides Notes Video
06 Jan, 2025 1. Introduction to Approximation Algorithms
Example: Load Balancing
09 Jan, 2025 2. Introduction to Linear Programming
Example: Vertex Cover
13 Jan, 2025 3a. Adaptive Rounding - I
Example: Bin Packing
16 Jan, 2025 3b. Adaptive Rounding - II
Example: Bin Packing (contd)
20 Jan, 2025 4. Randomized Rounding
Example: Set Cover
23 Jan, 2025 5a. General Techniques
Multiway Cut via Isolating Cuts
27 Jan, 2025 5b. Randomized Rounding - I
Multiway Cut
30 Jan, 2025 5c. Randomized Rounding - II
Multiway Cut (contd)
03 Feb, 2025 6. Primal-Dual Approximation
Vertex Cover
06 Feb, 2025 Class Cancelled
Remark: this class is canceled.
10 Feb, 2025 7a. Primal-Dual Approximation
Steiner Forest
13 Feb, 2025 7b. Primal-Dual Approximation
Steiner Forest (contd)
14 Feb, 2025 7c. Primal-Dual Approximation
Steiner Forest (contd)
Note: this is an extra makeup class
17 Feb, 2025 Class Canceled
Remark: this class is canceled.
19 Feb, 2025 8a. Primal-Dual Approximation
Facility Location - I
Note: this is an extra makeup class
20 Feb, 2025 8b. Primal-Dual Approximation
Facility Location II
24 Feb, 2025 9. Worksheet Discussions - I
27 Feb, 2025 10. Worksheet Discussions - II
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