| # | title | topic | type | difficulty |
|---|---|---|---|---|
| 301 | The header you cannot send | WebSockets | Multiple choice | Hard |
| 302 | The close code nobody sent | WebSockets | Multiple choice | Hard |
| 303 | send() never says no | WebSockets | Multiple choice | Hard |
| 304 | Connected to nobody | WebSockets | Multiple choice | Hard |
| 305 |
| Every client came back at the same instant |
| WebSockets |
| gap |
| Hard |
| 306 | Two hours after the incident, it happened again | WebSockets | gap | Hard |
| 307 | The reconnect that waited for an event nobody delivered | WebSockets | Multiple choice | Hard |
| 308 | The hotel wifi and the dead server look the same | WebSockets | Multiple choice | Hard |
| 309 | The same sort, without writing a sort | Sorting Algorithms | Coding | Medium |
| 310 | The same check, in one pass of methods | Algorithms & Recursion | Coding | Medium |
| 311 | The same prefix, without shrinking a guess | Algorithms & Recursion | Coding | Medium |
| 312 | Where is the black queen? | Algorithms & Recursion | gap | Medium |
| 313 | Look at the best capture first | Sorting Algorithms | gap | Medium |
| 314 | The move with no score went last, and the comparator never saw it | Sorting Algorithms | Multiple choice | Hard |
| 315 | Rank first, then file, and the falsy trap between them | Sorting Algorithms | gap | Medium |
| 316 | Bishop and knight are both worth three | Sorting Algorithms | Multiple choice | Medium |