Code on GitHub | Midterm Cheatsheet
What actually went wrong
Q3: didn’t finish reading the spec and constraint before coding. Missed a constraint that was written right there. not a knowledge gap, a discipline gap… even tho i knew that passing all public != full mark. fml. (i only recalled after)
Q4: attempted after Q1, realised it wasn’t simple, pivoted to Q2 -> Q3 -> back to Q4 with ~20 minutes left. didn’t get to solve it…
initially, i saw “points” and jumped into DFS. when it didn’t work, i kept patching, more directions, angle calculations, Pythagorean decomposition. each layer made it worse. the correct approach was geometry (90° rotation: (-dy, dx) and (dy, -dx)), not graph search. Simpler than everything i tried…
自信 -> 卡住 -> 慌 -> 越想越复杂 -> 更慌 -> 更加卡住 LOLL
这真的… 让我重新理解了 这句话：“越投入越不舍得放弃，越不放弃越陷越深。”
i spent days building a cheatsheet – but apart from regex, it was almost 0 help. the exam didn’t test what i memorised. it tested how i think under pressure. and in fact, most of the errors weren’t things i didn’t know – it was just me stressing myself out for no reason.
The real gap
to me, the gap isn’t technical — it’s discipline under pressure:
i should have:
- READ every constraint before writing a single line.
- CLASSIFY the problem type — “is this math or search?” — before coding.
- STOP after 10 minutes of no progress and re-read the problem, not the code.
- SIMPLIFY when it’s getting harder — complexity means wrong track.
- LET GO of sunk cost — only the remaining time matters.