+ 895 (div. 3)—26/3/2025 +
+
+
Decent.
+-
+
- + A: math intuition building. Jumped to assuming the problem + statement but it was much simpler. + Answer the problem only. + +
-
+ B: textbook simple problem that I struggle to mathematically
+ quantify being distracted by many components. In retrospect, I
+ should interpret the problem simply like:
+
+ Each trap has a known time I must return by. The answer is + therefore the minimum of these. +
+ I also just plug in \(ceil\) and \(floor\) until I find the + right answer (I'm not lying). Instead, note that for + \(s,k\in\mathbb{Z}\), + \[\frac{s}{2}>k\leftrightarrow\lfloor\frac{s-1}{2}\rfloor\geq + k\]. This simply "edges out" the fractional term to line up + cleanly with the divisor. +
+ - C: cooked. Practice number theory. +
- + D: took me a while because I was distracted with the moving + parts. Specifically, I forgot that I could choose the + permutation and that the question was merely asking to pick the + largest/smallest numbers on \(x\)/\(y\) slots respectively. End + solution was expressive and elegant. + Express the question and reframe the constraints in simple + but accurate terms. + +
-
+ E: Black-boxed a lazy segment tree (with the help of AI, I must
+ admit—I need to make a template).
+
+ Everything I did here was wrong and this problem showed an + embarrassingly fundamental flaw in my practice strategy. +
+ Namely, I should divide up practice time into: +-
+
- Contests, emphasizing speed and implementation +
- + Single problems, emphasizing specific learning objectives + +
+ In this problem, I immediately saw the application of the lazy
+ segment tree but decided to hold off on it, failing to find the
+ simpler prefix-XOR solution. Therefore, I not only wasted my time,
+ but also cemented in unrealistic practice (I would never do this
+ in a real contest) and worsened my virtual contest performance. As
+ for the prefix-XOR solution, focusing on just one/zero
+ corresponding elements and
+ walking through small examples
+ (i.e. "what happens when \(l=r\)?") would've help me pick up the
+ pattern.
+