Week 2: Setting up, and what computation means

Week 2 · 11 September 2026 · Data Structures (数据结构), Tsinghua University · XuetangX

Got everything set up and started the first real lectures.

1. What I worked on

Enrolled on XuetangX, registered on the Tsinghua OJ, set up g++ locally. Then watched 绪论 A on what “computation” means: rope computers, straightedge constructions, the four properties of an algorithm.

2. What was challenging, and how I handled it

I expected code and got geometry. The rope and straightedge examples seemed random, but they’re about what counts as a “basic operation” in different models. You can’t analyse an algorithm until you agree what one step is. The four algorithm properties (correctness, determinism, feasibility, finiteness) gave me trouble too. I kept mixing up feasibility and finiteness until the Hailstone sequence example made it click. A program that might run forever isn’t an algorithm, even if every step is simple.

3. How well I ran my own learning

Self-score: 100

I stuck with the parts that seemed pointless instead of skipping ahead, and they turned out to matter. Also caught the OJ same-email requirement by reading the docs before registering.

4. What I’ll do differently next session

Do all setup outside of class so the full period goes to content.

Evidence

Registered on XuetangX and the OJ. Notes on the four algorithm properties and Hailstone.