CS3233 - Competitive Programming
Introduction
This course aims to prepare students in competitive problem solving.
It will benefit NUS students who want to compete in ICPC, invited high school students (via CeNCE CS3) who want to compete in IOI (not just for NOI), and NUS students in general who aspire to excel in technical interviews of top IT companies, especially NUS current (2025++) ICPC donors: Jane Street, HRT, Jump Trading, Optiver, Citadel | Citadel Securities, and Huawei.
It covers techniques for attacking and solving challenging* computational problems. Fundamental algorithmic solving techniques covered include complete search, divide/reduce/transform and conquer, greedy, dynamic programming, etc. Domain specific techniques like graph, mathematics-related, string processing, and computational geometry will also be covered. Some additional topics may be included depending on how the semester progresses. Programming language libraries that are commonly used in problem solving will also be taught.
*We only study well-known/solved problems, not research problems.
Note: This introductory message will not be prominent the next time you visit this URL again. This behavior is normal. You can view it again by scrolling to the top of this page.
Course Registration
The quota of this class (S2 AY 2022/23 onwards) is 39, as that is the largest class size that is still considered a 'small course' where Bell Curve system does not have to be used. In 16+ academic years of CS3233 classes, on average only ~20 NUS students were enrolled per year.
Useful information to help you decide on whether you should offline register for CS3233:
-
Do you have national (but preferably international) programming competition background before? Examples: SGP NOI (or IDN OSN, VNM VNOI, CHN NOIP, MYS MCO, PHL NOI, IND ICO, etc), IOI (especially the recent IOI 2024 or IOI 2023), ICPC (especially the recent ICPC Asia Jakarta, Hanoi, and/or Yokohama 2024), Facebook Hacker Cup, CodeForces rated rounds, etc?
The difficulty of this course is very extreme for those without such background... but typically those that satisfy the next requirement (see question 2) can survive just as well... We will study problems that require (advanced) data structure and/or algorithms that are typically asked in programming competitions, and we have to implement those solutions fast and without bug...
-
Did you score well (at least A-) in CS1010/variant and CS2040/variant (and preferably score A+ in all; CS3230 (and CS4234) are good to have but optional)?
This course has a very high performance bar and the average GPA of the students enrolled in the past academic years excluding recent AYs (cannot track anymore since AY 2019/20 onwards) were 4.57, 4.78 (remember, year 1 nowadays have much more S/U options), 4.3+, 4.33, 4.44, 4.43, 4.45, and 4.30 (out of 5.00), respectively. You will need special permission from the instructor (A/Prof Steven Halim) if you do not satisfy the pre-requisites listed above (the filter is there for your own good). PS: Getting at least A- in CS2030/variant is included as official pre-requisite of CS3233, but an exception can be made if all other indicators are good.
-
Are you OK to be tortured for one semester for a mere 4 units (your other courses may also suffer)?
You may have to take lighter set of other courses or be ready to S/U other courses or to rush course project submissions (for project-based courses that have STePS on Wednesday night of Week 13 — no longer clash with CS3233 Monday night classes) or to rush final assessment preparations for other courses only during study week (no final assessment for CS3233). Please do NOT take CS3233 course with another course that is known to be challenging/demanding (e.g., the 5 units CS3217 in Sem2, among others) unless you are very confident of yourself and have historical academic performance to back that up. Moreover, your ego may be hurt if some of the young NOI trainees (Sec2-JC2 students) beat you in (many) CS3233 contests (a few guest students may now return to F2F mode onsite at PL2-TBC). Try to ask CS3233 seniors who have taken (and survived) this course before applying, or read their public stories, e.g., Lim Jay Ching (exchange from University of Waterloo).
-
Are you thinking on applying to top (or emerging) IT companies like NUS current (2024/25; list to be refreshed by January 2025) ICPC donors: Jane Street, HRT, Jump Trading, Optiver, Citadel | Citadel Securities, Huawei, or other large IT companies like Google, Meta (Facebook), Microsoft, Sea Group, etc in the future?
Some of our ex-CS3233 graduates are now in those companies :). See the CS3233 Hall of Fame to see the current known status of CS3233 past top students. Since a few AYs ago, many of these company (HR) reps will (e-)visit some of our (mini) contests and give prizes and/or recruitment talks which may be (much) faster than normal application route... Some seniors have cited that these direct connections with top IT companies is actually one of the nicest features of CS3233...
-
Can you code in C++ (primary language), Python (second choice), and/or Java (third choice)?
We will use C++ (17), Python (3), and Java (17) in CS3233 (in that order :O). In this course, we are expecting students to be multi-lingual :O. Although a few ex-students had survived CS3233 with only (or mostly) Java and/or the slower Python, they struggled more compared to those who are well versed in C++ (fastest programming language for programming competitions). Since AY 2018/19, Python (3) has been used and has given some advantage at certain problems for students who master this language. However, Python code is usually slow (albeit usually also shorter). An algorithm written in Python may get TLE while the same algorithm written in C++/Java pass the time limit.
-
Do you want to learn interesting data structures, algorithms, (other programming language especially if C++ is not your primary language) and more importantly: On how to apply them properly — from teaching staffs who are deeply involved in such programming competitions?
Instructor: Associate Professor Steven Halim, current CeNCE Director, Singapore IOI team leader, ICPC Asia Pacific Championship 2025 Contest Director (also Asia Singapore Regionals 2015 and 2018), the author of Competitive Programming text book (the official text book of this course, we will use CP4 Book 1 and Book 2), former Deputy Director for IOI 2020 and IOI 2021 in Singapore (online competitions), former NUS ICPC coach (5x ICPC World Finals Coach Award).
Rating (out of 5.0) Jan-Apr 2025 (max 39) Jan-Apr 2024 (n=34) Jan-Apr 2023 (n=31) Jan-Apr 2022 (n=28) Jan-Apr 2021 (n=18) Jan-Apr 2020 (n=12) Course feedback (SoC avg lvl 3000 ~3.9) ≥ 4.4 (tgt) 4.4 ▼ 4.9 (PB) ▲ 4.7 ▼ 4.8 ▼ 4.9 (PB) Course difficulty (SoC avg lvl 3000 ~3.8) ≤ 4.3 (tgt) 4.3 ▼ 4.6 (PW) ▲ 4.3 == 4.3 ▲ 4.2 Prof Halim's teaching (SoC avg lvl 2000 ~4.2) ≥ 4.5 (tgt) 4.6 ▼ 4.9 (PB) ▲ 4.8 ▼ 4.9 (PB) == 4.9 (PB) Qualified Teaching Assistant(s):
- TBC
- [and a few other behind-the-scenes problem setters for midterm and final contests]
Usually, CS3233 TAs have teaching feedback rating of around ~4.5 too (i.e., very good).
TA will be mostly available in NUS ICPC Lab (COM1-02-15), especially every Monday, 4.00-5.15pm to answer any CS3233/Competitive Programming queries, if any. - Are you OK to have your coding style 'somewhat damaged' because of this course?
Known damages are (illustrations are in C++), but not limited to:
- One character variable names (why type more than necessary), e.g., int i,j,k,l,m,n,u,v,w,x,y; (PS: i,j,k,l for up to 4-nested loop counter variables, m,n for number of edges/vertices of a graph, u,v,w for reading directed edge (u → v) with weight w, and x,y for 2D Cartesian coordinate system)
- Putting most of those variables as global variables (so that you never have to pass them as function parameter(s) — even by reference, especially the heavy ones like multi-dimensional arrays — to reduce 'out of stack space'/'stack overflow' issue)
- Intentional memory wastage by declaring big arrays as global variable (usually DP table) as big (or slightly bigger) as the problem statement says, e.g., int memo[1000][1000][2]; although we may only use parts of it on many smaller test cases
- If local (loop) variables are needed, use for-loop's initialization part (why waste additional lineS), e.g., for (int i=0,ans=0,flag=1;i<N;++i){...}
- Using autos everywhere and let the compiler do the variable type deduction work, e.g., for (auto& [v,w]:AL[u]){...}
- No comment (compiler doesn't need that to compile your code and you won't read your own code after end of contest/max 5 hours, so why write comments?)
- No function other than int main() unless you need to write a recursive function (your compiler just need this to run your code!)
- No space unless absolutely necessary (your compiler understands that :O), e.g., for(sum=i=0;i<N;++i)sum+=(A[i]>0?A[i]:0);
- One-liner-ing selection/repetition command/body if they are short, e.g., if (x>0) ++y,++z;, for (int i=0,j=1;i<N;++i,j*=2) or while (scanf("%d",&N),N){...} (yes, you can use commaS)
- Use (uhuk... nested...) ternary operation (condition1)?(condition2?if_1true2true:if_1true2false):(if_1false); as far as possible if that helps you to one-liner several standard if-elseif-else lines...
- Inlining (and one-liner-ing) short functions like inline inside(int r,int c){return r>=0&&r<R&&c>=0&&c<C;} for slightly faster speed
- As we want to shorten SLOC as far as possible, obviously we do not need to use blank line to separate logical blocks of code
- Excessive usage of constants/macros and typedefs, e.g., const int INF=1e9; const int MOD=1e9+7; typedef long long ll; typedef tuple<int,int,int> iii;
- Use bitmask operations whenever possible, e.g., printf("%d\n", __builtin_popcount(m));
- Including all libraries upfront, much more than possibly necessary, to avoid silly compilation errors albeit (slightly) increase compilation time, e.g., #include <bits/stdc++.h>
- 'Hack' C++ STL defaults to suit our needs, e.g., inserting negated input integers into priority_queue<int> pq; to make it into a Min-PQ instead of default Max-PQ (instead of definining our own comparison function)
- Intentional memory leaks, e.g., instead of wasting runtime 'free'ing deleted vertices in a pointer based segment tree, we just re-initialize a new segment tree for another test case (especially after seeing memory limit = 2GB, for example)
- On some rare occassions, we use the 'forbidden' goto statement...
- Using C++ operator shortcuts as far as possible, e.g., ++i; i*=2; i%=7;
- using namespace std (as there is no other namespace to consider in a short C++ program)
- And many scary stuffs that are hated by SE purists, e.g., fellow SE professors in SoC Prof Ben, Prof Damith, et al...
Fortunately, it is known that past CP-ers can somehow undo these damages to return back to normal SE practices, e.g., this one (so don't worry my fellow SoC SE colleagues :).
If you have read all (scary) questions above and are still interested, simply complete this application form to join CS3233 S2 AY2024/25 for offline registration before round 3 (the last day of application). The offline registration will be closed as soon as the number of students hits 39 accepted NUS students with CodeForces (max) rating of ≥ 14001299 (and/or special exceptions)
To minimize the annual attrition rate on Week 02 (Drop without penalty) and also :O on Recess Week (Drop with a 'W' grade, it happens!), the pre-acceptance selection will be made reasonably rigorous, i.e., by showing Prof Halim that the applicant has at least CodeForces (max) rating of ≥ 14001299 (naturally talented, PS: this is a more accurate predictor of potential CS3233 grade) by Tuesday, 31 December 2024, 23.59
Note: This course registration section will not be prominent from Monday, 09 January 2025 onwards (Week -01). This behavior is normal. You can view it again by scrolling to the top of this page.
News
| Date | News |
|---|
Ranklist
This list will be updated with S2 AY 2024/25 accepted students over time (last update: Mon, 30 Dec 24, 3.30pm).
It seems that this time, the max-CF cut off can be lowered a bit to ≥ 1299 (TBC).
Other students below who are interested to take CS3233 has to wait until Jan-Apr 2026.
Prof Halim actually still have 4 more slots (39-35 = 4), so the following redacted students can try appealing before Fri, 10 Jan 25 (EduRec round 3).
| No | Flag and Name | CF |
|---|---|---|
| 36 |  Try in 2026? |
1276 ??? |
| 37 | Try in 2026? |
1249 ??? |
| 38 | Try in 2026? |
1237 ??? |
| 39 | Try in 2026? |
1234 ??? |
| > 39 | Try in 2026? |
1229 ??? |
| > 39 | Try in 2026? |
1195 ??? |
| > 39 | Try in 2026? |
1166 ??? |
| > 39 | Try in 2026? |
790 ??? |
| > 39 | Try in 2026? |
0 ??? |
| > 39 | Try in 2026? |
0 ??? |
Senior students (for CS3233R only): Ong Weng Qi.
Senior students (lurking as guest students): Ho Hong Wei, Tan Kwang Thiag.
Lesson Plan
| Week | Self Reading from CP4 before class (Flipped Classroom) |
Homework (Mon, 9.00am) |
Contest + Debrief/Donor Talk (Mon, 5.30-6.45-7.15pm, PL2) |
Class Topics (Mon, 7.30-9.00pm, PL2) |
|---|---|---|---|---|
| Past classes more than one week ago are hidden so that we can focus on the current and future classes, but you can restore them by clicking 'Show Past' button above | ||||
|
-06/-05/ -04/-03/ -02/-01 |
As many pages from CP4 Book 1+2; at least from preface up to the end of Chapter 4 (the entire Book 1 basically); Note: For the actual semester, you must have a(n electronic) copy of CP4 (both book 1+2) to go through this course successfully; if you don't already have both books, go to lulu.com to get a (legit) copy. |
Lots of preparatory work especially for those who do not have competitive programming background yet Optional Kattis set #00 starts on Monday, 06 Jan 2025, 21:00 SGT |
No contest yet; But if you are not a multi-lingual programmer yet, pick up both C++17 (main), Python3 (secondary), and Java17 (tertiary) by yourself during holiday time | At home: Set up a (free) Codeforces account, then use Dec24+early Jan25 holiday (~3-4 weeks) to get ≥ 1400 rating in CodeForces and/or set up a (free) Kattis (open) account, then get ≥ 1000.0 points (~500 AC of ~2 pointer problems, see first ~5+ pages sorted based on Kattis difficulty ratings :O), use Prof Halim's classification here) in Kattis by Tue, 31 Dec 24, 23:59 (or MUCH earlier) to ensure course acceptance, familiarize yourself with Ubuntu 22 LTS with GNOME desktop, or self-read the older teaching materials in this public website |
|
01 13 Jan |
Preface to Chapter 1 (all pages) plus simple Ad Hoc problems in Chapter 2+3+9 |
Optional Kattis set #00 due The official Kattis set #01 starts |
Mock Ad Hoc (after first lecture) |
Let's Talk CP Introduction; Brief Course Admins; Focus on delivering some "Wow Moments"; A Bit of C++17, Python3, Java17, Mock/Preview Contest (not graded, but has high standard) |
|
02 20 Jan |
Chapter 2; Focus on Section 2.2 and 2.4.3 Read the rest of Chapter 2 by yourself |
Solve Mock 01 B/C HW01 due Kattis set #01 due and Kattis set #02 starts (we repeat this pattern until Set #12) |
Mini 01 O(n1.5) Algorithms Money Contest funded by [TBC] |
Be A Librarian Mastery of Libraries (C++ STL, Python Standard Library, & Java API); Focus on Bit Manipulation and VisuAlgo: bitmask, ufds, fenwicktree (optional), and segmenttree Decision to Drop CS3233/R without penalty by Fri, 24 Jan 25 (this time you can self-drop, but do inform Prof Halim first; hopefully we have 'no-one-drop-by-week-02' whenever possible) |
|
03 27 Jan |
Chapter 3, 4, 8, and 9; Focus on Section 3.1-2, 4.2.3, 4.4.2-3, 8.1-8.2, 8.6 (some NP-hard/complete problems with complete search solution), 9.20, and 9.21; Read Section 3.3 (DnC) too, especially about BSTA |
Solve Mini 01 B/C HW02 due Kattis set #02 due |
Mini 02 Libraries Money Contest funded by [TBC] |
(Binary) Searching for Answers Iterative Techniques (the fancier ones); Recursive Backtracking (bitmask-based, reverse thinking, data compression, etc); State-Space Search (harder form of SSSP, Graph modeling + BFS/Dijkstra's) with Meet in the Middle (Bidirectional Search); and finally, what if we can 'guess' the answer in Binary Search fashion? VisuAlgo: bitmask, recursion This AY 2024/25, CNY does *not* affect CS3233 CNY Eve (Reunion Dinner): 28 Jan 2025 PM (Tue) Day 1: 29 Jan 2025 (Wed) Day 2: 30 Jan 2025 (Thu) |
|
04 03 Feb |
Chapter 3, 4, 5, 6, 8, and 9; Focus on Section 3.5, 4.6.1, 5.4, 5.5, 5.8, 6.3, 8.3, 8.5, 8.6 (some NP-hard/complete problems with DP solution), 9.3, 9.7, and 9.29 Read Section 3.4 (Greedy) too |
HW03 due Solve Mini 02 B/C Kattis set #03 due |
Mini 03 Complete/Binary Search Money Contest donated by HRT |
The Art of Stenography (or Being Greedy) Dynamic Programming; "Instant" review of CS3230/CS4234 DP Materials; Focus on relationship between DP and DAG; Discussion of a few non-classic DP examples; Formulating non trivial DP states + transitions; DP vs greedy algorithm comparisons on some problems VisuAlgo: bitmask, recursion HRT class visit Mon, 03 Feb 2025 (details TBC) |
|
05 10 Feb |
Chapter 8 and 9; Focus on Section 8.4, 9.24, and 9.25; Optional: Read the Max-Flow material of CS4234 |
*short* HW04 due Solve Mini 03 B/C Kattis set #04 due |
Mini 04 DP or Greedy Money Contest Optiver |
How to Prevent Flood? Quick overview of Network Flow; Quick review of Ford-Fulkerson Max Flow algorithm variants: Edmonds-Karp and especially Dinic's (short comparison with Push-Relabel); Focus on Flow Graph Modeling skill and applications VisuAlgo: maxflow Optiver class visit Mon, 10 Feb 2025 (details TBC) |
|
06 17 Feb |
Chapter 4 and 8; Focus on Section 4.6 (Bipartite Graph) and 8.5; Then read Section 9.26, 9.27, 9.28, 9.29; We postpone Graph Matching in special cases of NP-hard problems (8.6) to Week 09 |
HW05 due Solve Mini 04 B/C Kattis set #05 due |
Mini 05 Graph1: Network Flow Money Contest donated by Jane Street |
(PS: We will do midterm team contest formation after Mini 05 so that you can practice as a team over Wk6 and/or recess week) Career Development Network, see Hall of Fame Quick overview of Graph Matching; Unweighted MCBM; Greedy Bipartite Matching, Focus on (Bipartite) Graph Modeling skill and applications; Quick Discussion on Weighted MCBM (Kuhn-Munkres/Hungarian algorithm); Review of DP bitmask for Graph Matching (any variant, but on small graph) -- (Edmonds' Matching algorithm shelved) VisuAlgo: maxflow, matching Jane Street class visit Mon, 17 Feb 2025 (details TBC) but we will extend the class to 9.15pm tonight Discover Citadel & Citadel Securities (Singapore) Fri, 21 Feb 2025 (details TBC) NOI 2025 Competition is this Sat, 22 Feb 2025 (online qualification contest, onsite for potential EGOI25 participants) |
|
Recess 24 Feb |
No class |
Kattis set #06, continued |
No class |
Although we are not supposed to have any face to face activity this week, nobody prevents you to keep solving Kattis problems (KS06 or more) 'by yourself' (or as a team of three) :). Again, peruse Prof Halim's classification here, this time probably aiming for the 3-4+ pointer problems... Prof Halim will organize the second ICPC Asia Pacific Championship, 27 Feb-02 Mar 2025 He will be extremely busy this week... Decision to Drop CS3233/R with 'W' grade by Sun, 02 Mar 25 |
|
07 03 Mar |
Re-read Week 01-06 reading materials and CS1020/2040/C/S stuffs; Re-read "standard" CS2040/C/S graph topics by yourself (Section 4.1-4.6) |
HW05 (special) due Kattis set #06 due |
Week01-06 + CS2040/C/S 5.15-9.45pm (4.5h) Money Contest funded by NUS ICPC Endowment Fund |
No lecture, we will do Midterm Team Contest VisuAlgo (for self-review): heap, hashtable, bst, graphds, dfsbfs, ufds, mst, sssp Midterm Team Contest (recent 3 AYs only): Midterm Team Contest (28 Feb 22) Midterm Team Contest (27 Feb 23) Midterm Team Contest (04 Mar 24) Our Midterm Team Contest (03 Mar 25) is on Kattis Starts at 5.15pm SGT, ends at 9.45pm SGT (4.5 hours) |
|
08 10 Mar |
Chapter 8; Focus on the Section 8.6; Optional: Read the first 1/3 of CS4234 material |
HW06 due Solve Mini 05 B/C (upsolve some non AC Midterm Contest problems by yourself, optional) Kattis set #07 due |
Mini 06 Graph2: Matching Money Contest donated by [TBC] |
Coping with (NP-)hard Problems Summary of 2/3 of CS4234 - Optimisation Algorithms (except local search) in CS3233 style. VisuAlgo: mvc, steinertree, tsp |
|
09 17 Mar |
Chapter 5 and 9; Focus on Section 5.3-5.6 + 9.36; Read the rest of Chapter 5 by yourself; Plus Section 9.9, 9.11, 9.15, 9.16, and 9.30 |
HW07 due Solve Mini 06 B/C Kattis set #08 due |
Mini 07 (NP-)hard Problems Money Contest donated by [TBC] |
NUMB3RS Mathematics overview with a movie; Focus on Python/Java Big Integer, Combinatorics, Number Theory (Extended Euclid, Modular Inverse, Fermat's little theorem, Chinese Remainder Theorem), and a bit of Probability VisuAlgo: cyclefinding NOI 2025 Competition is this Sat, 22 Mar 2025 (onsite final contest) |
|
10 24 Mar |
Chapter 6; Focus on Section 6.6 + 9.45; Read the rest of Chapter 6 by yourself |
HW08 due Solve Mini 07 B/C Kattis set #09 due |
Mini 08 Mathematics Money Contest donated by [TBC] |
(we will take a class photo #1) A Glance at Bioinformatics String Processing; Focus on Suffix Trie, Suffix Tree, and Suffix Array; a bit of String Hashing VisuAlgo: suffixtree, suffixarray Fri, 28 Mar 2025 is chosen as NUS well-being day S2 AY 2024/25 This is to link with Hari Raya Puasa PH next Monday Also, NUS Online Teaching Feedback opens this Fri You can already start declaring your vote about this course |
|
11 31 Mar |
No class |
Kattis set #10 due (automatic) |
No class |
No class Hari Raya Puasa Public Holiday |
|
12 07 Apr |
Chapter 7; Focus on Section 7.2, 7.3, 9.5; Also Section 8.7 (problem decomposition) Read the rest of Chapter 7 by yourself |
HW09 due Solve Mini 08 B/C Kattis set #11 due |
Mini 09 String Money Contest donated by [TBC] |
(we will do final team contest formation after Mini 09) (we will then do a no-longer-optional CS3233 Final Online Quiz (7.20-7.30pm)) (we will take another class photo #2 if #1 was not that good) Inside Video Games (Computational) Geometry; Focus on Algorithms on Points, Lines, a bit of 3D Geometry, and Polygon, Art Gallery Problem VisuAlgo: polygon, convexhull (we will run a short last lecture to close the course and may extend beyond 9pm) The Last Lecture (8.50-9.15pm) |
|
13 14 Apr |
The entire CP4 book 1+2 and beyond Do not forget to give your official NUS Online Teaching Feedback after final team contest is over |
HW10 due Solve Mini 09 B/C Kattis set #12 due |
Week01-12 stuffs 5.15-9.45pm (4.5h) Money Contest funded by NUS ICPC endowment fund Join NUS ICPC team selection (~Late August 2025?) |
No lecture, we will do Final Team Contest VisuAlgo (for self-review): maxflow, matching, mvc, steinertree, tsp, cyclefinding, suffixtree, suffixarray, polygon, convexhull Final Team Contest (recent 3 AYs only): Final Team Contest (11 Apr 22) Final Team Contest (10 Apr 23) Final Team Contest (15 Apr 24) Our Final Team Contest (14 Apr 25) is on Kattis Starts at 5.15pm SGT, ends at 9.45pm SGT (4.5 hours) No final assessment, go and save your other courses after tonight Good Friday and Easter Sunday this Week |
Hall of Fame
This table records the previous top students of CS3233 under Prof Halim (rank 1 up to at most rank 3) of that Academic Year and their current known job* as per last contact with Prof Halim (or as indicated by their latest LinkedIn update).
| AY (Iteration) | Rank | Flag and Name | Best ICPC Record | Job* |
|---|---|---|---|---|
| 08/09 (1) | 1 |  Ngo Minh Duc |
WF 09 (HM) & 10 (HM) | Addepar (US) |
| 08/09 (1) | 2 | Nguyen Hoanh Tien |
WF 09 (HM) & 10 (HM) | Microsoft (US) |
| 09/10 (2) | 1 | Trinh Tuan Phuong |
WF 12 (HM) & 13 (joint-48) | Quantcast (SG) |
| 10/11 (3) | 1 |  Koh Zi Chun |
WF 12 (HM) | Microsoft (US) |
| 10/11 (3) | 2 |  Harta Wijaya |
WF 12 (HM) & 13 (joint-48) | Meta (US) |
| 11/12 (4) | 1 |  Yang Mansheng |
N/A | DTL (SG) |
| 12/13 (5) | 1 | Nguyen Tan Sy Nguyen |
WF 13 (joint-48) & 16 (joint-14) | Anduin (VN) |
| 13/14 (6) | 1 | Nathan Azaria |
WF 14 (joint-19) & 15 (joint-28) | Roblox (US) |
| 13/14 (6) | 2 | Jonathan Irvin Gunawan |
WF 14 (joint-19) & 15 (joint-28) | Meta (SG) |
| 14/15 (7) | 1 | Stefano Chiesa Suryanto |
Asia Singapore 15 (4th) | Hearth (US) |
| 14/15 (7) | 2 | Vu Dinh Quang Dat |
WF 15 (joint-28) & 18 (joint-56) | DTL (SG) |
| 15/16 (8) | 1 | Nguyen Quang Dung |
Asia Phuket+Singapore 15 (10th) | [a private hedge fund] |
| 15/16 (8) | 2 | Truong Ngoc Khanh |
Asia Singapore 15 (20th) | ByteDance (SG) |
| 16/17 (9) | TA/Exempted | Gan Wei Liang |
Asia Manila 17+Nakhon Pathom 18 (1st) | Jump Trading (SG) |
| 16/17 (9) | 1 | Tan Jun An |
Asia Singapore 18 (16th) | Google (SG) |
| 16/17 (9) | 2 | Agus Sentosa Hermawan |
WF 17 (joint-20) | Glints |
| 17/18 (10) | TA/Exempted | Ranald Lam Yun Shao |
Asia Manila 17+Nakhon Pathom 18 (1st) | Jump Trading (SG) |
| 17/18 (10) | 1 |  Robin Christopher Cham Yu |
Asia Jakarta 18+20 (3rd) | Sea Group (SG) |
| 17/18 (10) | 2 | Sergio Vieri |
Asia Jakarta 18+20 (3rd) | Jane Street (HK) |
| 17/18 (10) | 3 | Bay Wei Heng |
WF 2019 (joint-62) & 20 (honor) | Jane Street |
| 18/19 (11) | Exempted | Bernard Teo Zhi Yi |
WF 19 (joint-62) & 20 (honor) | HRT (SG) |
| 18/19 (11) | Exempted | Lim Li |
WF 22 (joint-61) | Stripe |
| 18/19 (11) | 1 | Nguyen Dinh Quang Minh |
WF 2018 (joint-14) & 2021 (HM) | [a private hedge fund] |
| 18/19 (11) | 2 | Tran Tan Phat |
Asia Jakarta 19 (1st) | [Graduated] |
| 18/19 (11) | 3 | Herbert Ilhan Tanujaya |
N/A | Allium |
| 19/20 (12) | Exempted | Gabriel Goh Kheng Lin |
Asia Jakarta 20 (3rd) | [Graduated] |
| 19/20 (12) | 1 | Vuong Hoang Long |
WF 21 (HM) | Pendle Finance |
| 20/21 (13) | Exempted | Zhang Guangxuan |
WF 21 (HM) | Jane Street |
| 20/21 (13) | Exempted | Clarence Chew Xuan Da |
Asia Jakarta 20 (3rd) | NUS PhD student |
| 20/21 (13) | 1 | Dan Alden Varsobia Baterisna |
Asia Jakarta 23 (4th) | [Graduated] |
| 21/22 (14) | Exempted | Huang Xing Chen |
Asia Ho Chi Minh City 22 (3rd) | 4th year UG |
| 21/22 (14) | Joint-1 | Rama Aryasuta Pangestu |
AP 24 (2nd); WF 24 (Silver) | 4th year UG |
| 21/22 (14) | Joint-1 | Bui Hong Duc |
AP 24 (2nd place); WF 21 (Bronze) & 24 (Silver) | 3rd year UG |
| 21/22 (14) | 3 |  Nyamdavaa Amar |
AP 24 (2nd place); WF 24 (Silver) | Tower Research Capital |
| 22/23 (15) | Exempted | Jeffrey Lee Chun Hean |
World Finalist 2023 (Apr 2024, HM) | 2nd year UG |
| 22/23 (15) | Exempted | Teow Hua Jun |
2nd place in ICPC Asia Hanoi 2024 | 2nd year UG |
| 22/23 (15) | 1 |  Yeung Man Tsung |
Twelfth place in ICPC Asia Jakarta 2023 | 2nd year UG |
| 22/23 (15) | 2 | Tan Chee Heng |
Twelfth place in ICPC Asia Jakarta 2023 | 3rd year UG |
| 23/24 (16) | 1 | Nguyen Cao Duy |
N/A | 2nd year UG |
| 23/24 (16) | 2 |  Watanabe Yuto |
2nd place in ICPC Jak23+24 | 2nd year UG |
| 23/24 (16) | 3 | Nguyen Nhat Minh |
World Finalist 2023 (HM) | 2nd year UG |
Scoring Scheme for CS3233 S2 AY 2024/25
This section will be updated soon
There are two big scoring components: SP(eed) (from live contests, up to 57%) and DI(ligence) (from non-speed-related stuffs, up to 57%).
IMPORTANT change for S2 AY 2024/25 onwards: each component is now capped at 50%, i.e., one cannot just be very speedy (get 57% from SP component but then get a bit lazy) or just be very diligent (get 57% from DI component bu then actually not good during contests).
The theoretical max is therefore 114% back to 100% again, with just 60% needed to secure at least a B+ grade in this extremely competitive course.
The SP(eed) component is further divided into two sub-components: M(ini)C(ontest) (up to 36%) and T(eam)C(ontest) (up to 22%).
The DI(ligence) component is further divided into four sub-components: H(ome)W(ork) (up to 15%), (Problem)Bs (up to 10%), K(attis)S(ets) (up to 12%), and Ac(hievements) (up to 20%).
MC = Weekly Mini Contest (36%)
9 Weekly Mini Contests, three problems in 75 minutes, using https://cs3233.com (new system) or fallback to Mooshak (old system).
(9 weeks x (3%+0.5%+0.5%)/week = 36%).
- very easy/easy/warm-up/1-2 simple CP technique(s): 1%.
- medium/last week material, 2%; may have weakened subtask for 1%.
- usually very hard and from topics not specifically taught in class (or taught in latter part of the class -- suitable for senior students only), for CS3233R students, bonus 0.5% for CS3233/R students who can get this AC in contest time.
Occasionally (if Prof Halim is not that lazy), we may open problem D (or even E) which is (are) the easier form of problem B/C. We give bonus 0.5% for top 3 in each mini contest. We use strict binary grading (Accepted or not Accepted: Wrong Answer, Time Limit, Memory Limit, Runtime Error, etc) for our contests.
Two Team Contests (21%)
1 Midterm Team Contest (10%+0.5%=10.5%, 10 "original" problems, worth 1.0% each).
1 Final Team Contest (10%+0.5%=10.5%, 10 "original" problems, worth 1.0% each).
Bonus 0.5% for top 3 teams in both team contests.
Team size is three students.
If the class size is not divisible by 3, the last team can have 4 or 5 members.
Weekly Homework (15%)
10 Weekly Homework (10 weeks * 1.5%/week = 15%).
CP4 book 1+2 review + solve certain written exercises + update the lecturer, 1.5%.
Scoring scheme: 0% = no submission, 0.5% = poor, 1% = default score, 1.5% superb.
Problem Bs (10%)
Solve problem B of last week's mini contest at home, on your own pace, by next Mon 05.15pm (closed by the time TA consultation hour is over), if you fail to solve it during the live Mini Contest. Simply submit your code to cs3233.com (or to Mooshak), TA will check your last submission.
Scoring scheme:
0% = not AC in the actual mini contest and not attempted after one more week.
1% = managed to solve problem B during mini contest itself or before deadline.
There is no additional marks for solving problem C at home (for CS3233R students).
Kattis Set (12%)
We use NUS@Kattis for this semester.
Prof Halim selects eight targeted Kattis problems related to CS3233 topic of that week (Prof Halim has solved seven of them before with one problem that he has not solved before). To get 1% per week, student has to solve at least three (of any preferred difficulty level as indicated in Kattis) of the selected problems within the stipulated deadline (Monday night 09:00pm SGT of that week until Monday 05:30pm SGT of the following week). Note that Prof Halim can see all CS3233 class submissions at nus.kattis!
- Set #00, Competitive Programming Preview (not graded)
- Set #01, Ad Hoc
- Set #02, Data Structures and Libraries
- Set #03, Complete Search and easier BSTA+Other
- Set #04, CNY period: CS2040/C/S++ Basic Graph Review (Graph Traversal, MST, SSSP, APSP, Special Graphs)
- Set #05, Dynamic Programming
- NUS recess week (nothing is due this week)
- Set #06, Easier Mathematics (can be done over recess)
- Set #07, Greedy and Network Flow
- Set #08, Graph Matching and Miscellaneous 1
- Set #09, NP-hard Problems and harder BSTA+Other
- Set #10, Harder Mathematics
- Set #11, String Processing
- Set #12, Computational Geometry and Miscellaneous 2
Achievement System of CS3233 (20%)
One star = 1%, most achievements are manual entry:
- **** Active in class: Subjective title for students who participated well during various class activities (answering in-lecture questions, asking/answering questions in real life or in our Discord server, consultations (with Prof Halim/TAs on Mon 4.00-5.15pm), active in Kattis, etc), awarded by Prof Halim/TAs throughout the semester (max claim: 4 times/student).
- *** Surprise us: Managed to surprise the teaching staffs by giving a better/more elegant solution/pinpoint bug in lecture, etc anytime during the semester (max claim: 3 times/student).
- * High determination: Objective title for students who always diligently solve (AC) problem B of all 10 weekly contests (inclusive of problem B of the Mock contest), be it during contest time or as homework assignment. This achievement will be auto updated by this system at the end of the semester.
- ** Bookworm: Subjective title for students who diligently study and review CP4 book 1+2 by the end of Week12 (at least 10*1.5% - 0.5% = 14.5% score, i.e., at most one 1.0 with the rest 1.5). This achievement will be manually updated at the end of the semester. The two ** will only be given to the top 3 CP4 book reviewers in the semester.
- ***** Kattis apprentice: Obtaining ≥ 5000 Kattis points (5% — it is not impossible, e.g., Nicholas Russell Saerang (10.6K), marc-phua (9.7K), matthewng — hidden (9.2K), Artemis Ngoh (6.3K), Nicholas Foo Chuan le (6K), and bayweiheng (5.9K))/100 (3% — appear at ranklist page — there are ~13 NUS staff/students here)/200 (2%)/400 (1%) of Kattis ranklist by Sat, 10 May 2025, 23:59 (this achievement will NOT be updated instantly as this will keep changing every week).
- ***** CodeForces specialist: Given to student who also join CodeForces contests and attain (max) rating of at least 3000 (Red color) (5%)/2400 (Red color) (4%)/2100 (Orange color) (3%)/1900 (Purple color) (2%)/1600 (Blue color) (1%) by Sat, 10 May 2025, 23:59 (this achievement will NOT be updated instantly as this will keep changing every week).