Kacam.net

System design

评论 / 树形结构

三种树存储没有绝对优劣,所以得先问产品要什么。

Copy the prompt, then pick a model. It plays the interviewer and asks you through it scene by scene instead of handing you the answer.

On a phone with the app installed, the system opens the app directly. Links cannot open external apps inside WeChat — open it in a browser first.

The copied text ends with the answer key the model grades you against. Don't read it yourself first — working it out on your own is the point.

最短的一道,适合热身,或者当另一道题做完之后的补充。

价值不在难度,在「先问产品要什么,再决定用哪种存储」这个动作 —— 三种方案真的没有绝对优劣。

★★☆☆☆ · about 25 min · Tests: 三种树存储的取舍、软删的连锁反应、计数一致性、排序与分页

Cross-cutting patterns this one leans on

Databases Caching Rate limiting, shedding, breaking, degrading

Have you done this one?

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Notes from people who did this one

Nobody has written yet. After you run it, say what came out of the conversation — which scene stumped you, which conclusion you changed afterwards.

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How to use this

How to start

  1. Pick a question, open it, copy the prompt.
  2. Paste it into a brand-new conversation — not one where you already discussed this question, or the model follows your old answers.
  3. Say nothing. Wait for its first question.

Four commands you can call out at any time

  • 跳过 move to the next scene now
  • 提示 give a direction, not the answer
  • 直说吧 spell this point out in full, then keep pressing on the trade-offs
  • 复盘 jump to the wrap-up and print the review card

Three traps

  • Don't do two questions in one conversation — context from the first makes the model prejudge your level.
  • Don't look up the answer the moment it asks. Being stuck for 30 seconds is itself useful information.
  • When it starts praising you, point it back to rule five — feeling validated crowds out noticing what you missed.

Suggested order: start with the cross-cutting drill as a parts test, use the short-link question to get used to the flow, then pick by the direction you interview for, and keep redoing the one about your own project.