No bullshit, opinionated tier list of the best problem solving resources.
Tier List
F
Codeforces Blogs
| Resource | Note |
|---|---|
| Problem Topics | Categorizing problems by topic. |
| CSES DP Editorial | Detailed solutions for CSES DP section. |
| Non-trivial DP Tricks | Advanced DP techniques tutorial. |
| All Good Tutorials | Master list of CF tutorials. Bookmark this. |
| Segment Trees | Efficient and easy segment tree implementation. |
| DP Tutorial & Problem List | Comprehensive DP guide with curated problems. |
| Sliding Window Techniques | Handling non-invertible operators. |
| Collection of Techniques | Miscellaneous useful tricks. |
| Bitwise for Beginners | Intro to bit manipulation. |
| Generating Functions | GF in competitive programming. |
| Unordered Map Hacking | How to not get hacked on unordered_map. |
| C++ Lambda Tutorial | Deep dive into lambdas. |
| Gym Contests w/ Editorial | List of gym contests that have editorials. |
Japanese Resources
| Resource | Note |
|---|---|
| AtCoder Educational DP | Classic DP contest. Must do. |
| 競プロ典型 90 問 | 90 typical problems covering all topics. |
| A Way to Practice CP | How to practice competitive programming. |
| Yellow Coder Guide | Guide to reaching yellow rating. |
| Water Coder Guide | Guide with 100 curated problems. |
| maspy HP | Problem explanations from a top coder. |
| Ternary Search | Ternary search tutorial. |
| BIT Tutorial | BIT implementation guide. |
| ei1333 Templates | Competitive programming library. |
| misuki Templates | Another solid CP template library. |
Other Resources
| Resource | Note |
|---|---|
| Yuihuang Notes | Taiwanese CP notes and solutions. |
| Berlekamp-Massey | Linear recurrence made easy. |
| zhoukangyang Blog | Chinese CP blog with advanced topics. |
| bqi343 Notebook | Benq's legendary CP notebook. |
| Code Library | Huge collection of CP templates. |
| justiceHui FFT | Clean FFT implementation. |
| Rolling Hash | Rolling hash template. |
Tools
| Tool | Note |
|---|---|
| AtCoder Problems | Track AtCoder progress. Virtual contests. Essential. |
| CF Visualizer | Visualize your Codeforces stats and progress. |
| CFTracker | Track solved problems across CF contests. |
| CLIST | Aggregates contests from all platforms. Never miss one. |
| OI Checklist | Track progress on IOI/APIO/BOI problems. |
| Graph Editor | Draw graphs for debugging/visualization. |
| Virtual Judge | Practice problems from multiple OJs in one place. |
| Interval Visualizer | Visualize interval operations. |
| Is My Problem New? | Check if your problem idea already exists. |
| CF Problems Filter | Alternative CF problem tracker. |
| CF Recommender | Get personalized problem recommendations. |
| AtCoder Tags | Browse AtCoder problems by algorithm tag. |
Math
| Resource | Note |
|---|---|
| OEIS | On-Line Encyclopedia of Integer Sequences. Indispensable. |
| OTIS Excerpts | Evan Chen's olympiad training materials. |
| Project Euler | Math + programming problems. Great for number theory. |
| Art of Problem Solving | Alcumus adaptive problem trainer. |
| Online Math Contest | Japanese math competition platform. |
| IMO Shortlist Training | Practice IMO shortlist problems. |
| Evan Chen Beginner Guide | Where to start with math olympiads. |
| Mathematical Circles | Russian Experience. Classic problem solving book. |
| Olympiad Combinatorics | Comprehensive combinatorics for olympiads. |
| MathDash | Speed math competitions. |
| Alex Remorov | Canadian IMO training materials. |
| Canada IMO Training | Official Canadian IMO training site. |
| BOJ Olympiad | Korean OJ olympiad problems section. |