Study Reinforcement Learning

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problem sets

Homework

Problem sets in the style of a university RL course: theory, coding, and reading.

unreviewed draftNo one has checked this end to end. Treat the math, code, and citations as unverified. Source on GitHub.

Problem sets in the style of a real RL course (the Berkeley CS294 model: HW1 through HW5). Each homework combines theory questions, coding problems, and short reading. Solutions in a separate file, try the problems first.

The coding parts link to ../exercises/ (which are tested).

What’s here

HWTopicLecture(s)Status
HW1MDPs, Bellman equations, value iterationL01ready
HW2Policy gradients, REINFORCEL02planned
HW3Q-learning, DQNL03planned
HW4Actor-critic, PPOL04, L06planned
HW5Reward modeling, RLHF, DPOL09–L11planned
HW6GRPO and RL with verifiable rewardsL12, L15planned
HW7Agentic RL or offline RL (pick one)L16 or L19planned

How to use

Each hwNN/ directory has:

  • README.md: what the HW covers, what you should know going in, time estimate
  • problems.md: numbered problems (theory + coding + reading)
  • solutions.md: full worked solutions; try every problem first

Theory problems should take 10–30 minutes each with paper. Coding problems link to the matching exercises/NN/ (with starter, tests, reference solution, hints). Reading problems point you at specific Sutton & Barto chapters or original papers.

Why bother with paper-and-pencil theory in 2026

Because if you can’t derive the policy gradient theorem from scratch, you don’t actually understand what you’re optimizing: you’re just running someone else’s code. Same for the Bellman equations, the contraction proof for value iteration, the variance argument for baselines, the DPO derivation. The theory is short. Doing it once builds the intuition that makes the code make sense.