Tech Interview Drill (大厂技术面试)

Technical interviews at Chinese internet companies follow a recognisable pattern: an online test, two or three technical rounds that mix fundamentals (八股), hand-written algorithms (手撕), system design and a deep dive into the candidate's projects, then an HR round. Interviewers chase every answer with 追问 until they find the edge of what the candidate really knows. This skill builds a plan for the target role and runs mock rounds that do the same.

Write in Simplified Chinese unless asked otherwise. Company processes change; confirm the rounds with the recruiter.

Required Inputs

Ask for these if not provided:

• Target role and level: 后端, 前端, 客户端, 算法, 测试, 数据; campus (校招) or experienced (社招)
• Stack: for example Java, Go, C++, Python, JavaScript and React or Vue
• Projects on the CV, with the person's own role and numbers
• Interview date and hours a day available
• Weak areas, if known

Output Structure

1. Round map and plan

| Round | What it tests | Preparation | Days | Covering 笔试 (algorithms under time), 一面 (fundamentals and coding), 二面 (projects and design), 交叉面 or 主管面 (depth and judgement), HR 面 (motivation, expectations).

2. 八股 question bank by stack

Grouped, each with the answer points and the likely 追问. For example:

• 计算机网络: TCP 三次握手与四次挥手（追问：为什么是三次？TIME_WAIT 的作用？）; HTTP/1.1, HTTP/2, HTTP/3 的区别; HTTPS 握手
• 操作系统: 进程与线程; 虚拟内存; I/O 多路复用（select / poll / epoll）
• 数据库: MySQL 索引（B+ 树、最左前缀、回表）; 事务隔离级别与 MVCC; 慢查询排查
• Redis: 数据结构; 持久化（RDB / AOF）; 缓存穿透、击穿、雪崩
• Stack-specific: Java（JVM 内存模型、GC、并发包、Spring）, Go（GMP 调度、channel）, 前端（事件循环、浏览器渲染、React 或 Vue 原理）

3. Algorithms

A topic list in priority order (数组与双指针, 哈希, 链表, 二叉树, 回溯, 动态规划, 图) with three representative problems each, and the habits interviewers look for: clarify the input, state complexity, test edge cases out loud.

4. System design walkthrough

One worked example matched to the role (秒杀系统, 短链服务, Feed 流, 分布式 ID) using a fixed frame: requirements and scale estimate, API, data model, core design, bottlenecks, trade-offs.

5. Project deep dive

For each CV project: the 30-second summary, the hardest problem and the person's own decision, the numbers, what they would change, and the five 追问 an interviewer will ask.

6. Mock round

Questions one at a time. After each answer: 追问 until the edge is found, then a score (1 to 5) on correctness, depth and communication, with the missing points.

Quality Checks

• The plan covers every round the target company runs, with days allocated
• Every 八股 question has answer points and at least one 追问
• The system design example states a scale estimate and its trade-offs
• Every project script names the person's own decision and a number
• The mock round asks one question at a time and follows up before scoring
• No company's internal question list is presented as leaked or official

Anti-Patterns

• Reciting 八股 without understanding. The 追问 finds it in two questions.
• "We did X" in the project deep dive. Interviewers want what you decided.
• Silent coding. Think aloud; communication is scored.
• Design without numbers. A design with no scale estimate cannot be judged.

Example Trigger Phrases

• "下周字节后端一面，帮我模拟一轮。"
• "Java 八股文按优先级帮我列一下，附追问。"
• "帮我准备项目深挖，项目是一个订单系统。"
• "Run a mock technical interview for a Chinese tech company, frontend role."