今日固定时间表
三块窗口固定：08:50-10:55 系统设计，14:30-16:15 算法，20:30-21:15 口述。
| 08:50-09:20 | 08:50-10:55 system design 交叉追踪 - 逐域画 winning transaction：seat sold、bid wins at close、order accepted/executed。 |
|---|---|
| 09:20-09:55 | 08:50-10:55 system design 重复失败追踪 - 逐域画 duplicate reserve/bid/order/cancel/webhook，并写 safe retry response。 |
| 09:55-10:25 | 08:50-10:55 system design 最低分 re-attempt - 新故障 8 分钟闭卷：decision -> invariant -> failure -> recovery -> metric。 |
| 10:25-10:55 | 08:50-10:55 system design 验收记录 - 填 scorecard，核对 artifacts、anchors、DDIA links、Binary Search slots 和 production record。 |
| 14:30-16:15 | NeetCode Tag · Binary Search 三道题，每题 30m solve + 5m evidence，不能改 tag。 |
| 20:30-21:15 | 20:30-21:15 最终 oral synthesis：7 分钟英文讲完整 Week 5。 |
算法模块
连续 NeetCode Binary Search；每天 exactly 3 slots。
| # | Problem / mode | Pattern | Invariant | Bug risk | Time | Space |
|---|---|---|---|---|---|---|
| 1 | Maximum Candies Allocated to K Children NEW · 30m solve + 5m evidence | max feasible allocation | If each child can get x candies, any smaller x is feasible. | Division by zero lower bound; total children count overflow. | O(n log maxCandy) | O(1) |
| 2 | House Robber IV NEW · 30m solve + 5m evidence | min capability with greedy feasibility | Given capability x, greedy non-adjacent count is maximal. | Skipping incorrectly after chosen house; boundary k=1. | O(n log maxValue) | O(1) |
| 3 | Minimize the Maximum Difference of Pairs NEW · 30m solve + 5m evidence | min threshold with greedy pairs | If threshold x can form p pairs, any larger threshold can too. | Overlapping pairs due to not advancing by 2. | O(n log R) | O(1) extra |
Hello Interview 精确目录
保留 live canonical heading title；day page 使用 direct section anchors。
今日不新增 Hello Interview section anchors；使用前五天的 evidence 做 mock 和 synthesis。
DDIA 精确决策卡
只使用 Ch8 和 Ch10 中直接解决今天设计决定的小节。
| 项目 | 项目问题 | 精确 DDIA subsection | 改变的系统决定 |
|---|---|---|---|
| Cross-domain | When is full serializability necessary instead of a local conditional write? | Ch8 - 可串行化 | Use the smallest serializable boundary that protects the invariant; leave search, market display, and notifications as derived views. |
三域 trace 任务
Winning transaction标出唯一线性化点：seat hold/sold、accepted bid at close、brokerage order/execution state。
Duplicate/retry failure给出 stable idempotency key、重复返回语义、旧 owner/stale version 被拒绝的证据。
Projection boundary说明哪些读可以陈旧：seat map、highest bid display、market price UI；哪些写不能陈旧。
本日 artifacts
项目脚本、音频、PDF 和 mock evidence 从当天直接打开。
今日产出、修复与英语 recall
| 课程角色 | repair + scorecard + synthesis |
|---|---|
| 必须交付 | Week 5 scorecard：all headings disposed, artifacts pass, mocks/follow-ups recorded, READY_FOR_REVIEW。 |
| 修复规则 | 如果任一项目不能追出 winning transaction 和 duplicate failure，回到该项目 lecture/QA 再答一次。 |
| English recall | English recall: Strong consistency belongs on the invariant boundary; everything else can be a recoverable projection. |
Detailed lecture notes, audio, recall scripts, PDFs, Staff Q&A, and mock packs are archived locally and are intentionally not published on this site.