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Atcoder Beginner 382
Nov 30 2024
8:47 AM

It's been a decent while since I did one of these. Speed still seems to be ok.

Solves:

  • A @ 1 minute 6 sec. Very standard

  • B @ 4 minute 4 sec. Also standard

  • C @ 9 minute 10 sec. Wrote some montonic array & binary search

  • D @ 14 minute 49 sec. DFS-like ordered sequence builder

  • F @ 52 minute 12 sec. RMQ + range set segtree on sorted list

tags: programming atcoder contest-logs

fun trie problem
Oct 26 2024
10:27 AM

This problem is from today's atcoder beginner contest

You are given a list A of lowercase English strings.
For each string S in A, solve the following problem:

You can perform two operations to S:

- Delete the last character of S (if it is non-empty)
- Add any lowercase character to the end of S

Find the minimum number of operations to convert S into either the empty string or a string that comes before it in A.

This kind of screams trie...

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tags: programming atcoder contest-logs

ARC is scary
Oct 13 2024
1:44 PM

Took Atcoder Regular Contest 185 this morning. I had done one ARC virtual in the past, but that one had relatively more 'normal' questions than today's contest. I think it went alright? I don't really have a sense of scale with ARC yet.

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tags: programming atcoder contest-logs

Atcoder Beginner Contest 375
Oct 12 2024
10:06 AM

I should put more effort into these surely...

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tags: programming atcoder contest-logs

Atcoder Beginner Contest 374
Oct 5 2024
10:27 AM

Woke up 10 min before contest, slow start but wow.. good contest I think

...

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tags: programming atcoder contest-logs

le brick
Oct 1 2024
10:54 PM

vced ARC 058 w/ jasonwei

C was theoretically easy, construct from smallest digit, etc. but I messed up overflow case [twice] and that whole mess took like 30m total

D was fun combo, pathfinding nonsense that partition & track crossings kind of deleted

E was some DP that I failed, also managed to forget that complementary counting existed.. smh

didn't have anything substantial on F besides "knapsack" so ya

mid contest, definitely need to work on dp

tags: programming atcoder contest-logs

2011 IOI
Oct 1 2024
4:43 PM

Easier contest (by nature of its age) but still pretty fun. Due to schedule I started around 3 pm and therefore ended at 8, on both days, so didn't have much time to writeup each day separately.

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tags: programming ioi contest-logs

Atcoder Beginner Contest 373
Sep 28 2024
10:35 AM
  • A: trivial

  • B: invert array, trivial

  • C: trivial

  • D: pretty cool, restructure directed graph as an undirected graph w/ directed weight, DFS

  • E: possibly some sort of ranging and binary search, couldn't work out implementation

  • F: tried to run the knapsack dp as normal but store a best_cost[] alongside, and attempted to use some quasi-convexity and 2p to speed up choice but this did not work (AC x53, WA x5)

  • G: impossible wtf jasonwei orz

terrible perf lol. should I take the upcoming AGC? idk.

tags: programming atcoder contest-logs

2014 IOI day 2
Sep 19 2024
11:39 AM

Took the contest 2 days ago but was pretty busy yesterday (with some discrete math project skull) so doing writeup rn in school lmao

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tags: programming ioi contest-logs

2014 IOI day 1
Sep 17 2024
9:27 AM

Virtualed IOI14d1 yesterday. Due to time (18:30 - 23:30) I didn't feel like writing up last night, so I'm just doing this while bored at school :p

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tags: programming ioi contest-logs

Atcoder Beginner Contest 370 (and weird binary search?)
Sep 7 2024
10:48 AM

Decent contest. Started 6 min late bc I lost track of time while debugging some cses problem :/ but it was fine..

ABC were basically trivial, C had a pretty simple pattern (provable by optimal-choice argument) which I got relatively quickly. D was an adventure, though.

Task essentially asks us to determine in a 2d bitfield the...

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tags: programming atcoder contest-logs

d1 fumbler (me)
Aug 31 2024
11:39 AM

I did the ABC today: https://atcoder.jp/contests/abc369

The fumbling started on problem A, where I misread the input format and consequently got 2 WA (don't worry why this caused 2 WA and not 1). Then I did a dumb thing...

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tags: programming atcoder contest-logs

2018 IOI day 1
Aug 20 2024
12:04 AM

Completed the second half of IOI18. Performance was kinda eh, but wasn't expecting much :clown:


0:00 - 1:30

Solved Combo. Essentially the construction I found was to guess the next 2 bits in the sequence over the course of two queries: there were 3^2 = 9 possible arrangements of next bits, and each query had three possible return values, which worked out to a...

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tags: programming ioi contest-logs

Getting trolled by subtasks (again)
Aug 18 2024
10:48 PM

I was attempting some afternoon funsies for most of today, which I basically totally bricked.

Here is a hopefully not too scuffed breakdown. (would say it has spoilers, but I barely solved any of the actually interesting problems so nah)

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tags: programming ioi contest-logs

CCC 2017 Senior Division
Jul 23 2024
2:41 PM

Simulated this contest today - here are my notes and solutions!

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tags: programming ccc contest-logs

CCC 2018 Senior Division
Jul 22 2024
8:23 PM

Not much, just my solutions and some comments from my practice contest today :)

Spoiler warning - contains full solutions!

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tags: programming ccc contest-logs