Theory of Problem Solving
Deconstructions of algorithms and competitive programming problems — from the ICPC, IOI, Codeforces, USACO, TopCoder, and beyond. Not just the answers: each editorial reconstructs the full path to a solution — the initial observations, the ideas that failed, and the insight that finally worked.
I'm a 2× World Finalist at the International Collegiate Programming Contest, representing the University of Waterloo in 2013 (St. Petersburg) and 2015 (Morocco) — where we finished 13th in the world, 3rd in North America, and 1st in Canada — and a 2× ICPC World Finals Judge. You can find me as dojiboy9 on Codeforces.
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| Status | Title | Judge | Round | Index | Statement | Published |
|---|---|---|---|---|---|---|
| ✓ | Lost Civilization | Codeforces | Round #1082 (Div. 1) | Problem A1/A2 | [URL] | 2026-08-31 |
| ✓ | Unique Values | Codeforces | Round #1093 (Div. 1) | Problem B1/B2 | [URL] | 2026-08-30 |
| ✓ | Grid L | Codeforces | Round #1093 (Div. 1) | Problem A | [URL] | 2026-08-25 |
| ✓ | Even If the World Turns | Codeforces | Round #1116 (Div. 1) | Problem C | [URL] | 2026-08-10 |
| ✓ | How Long Until Nothing Remains? | Codeforces | Round #1116 (Div. 1) | Problem D | [URL] | 2026-08-09 |
| ✓ | AI Finds Nothing Here | Codeforces | Round #1105 (Div. 2) | Problem B | [URL] | 2026-08-07 |
| ✓ | Another Popcount Problem | Codeforces | Round #1105 (Div. 2) | Problem A | [URL] | 2026-08-07 |
| ✓ | Decidophobia | Codeforces | Round #1105 (Div. 1) | Problem B | [URL] | 2026-08-06 |
| ✓ | Nim Game Is XOR Game | Codeforces | Round #1105 (Div. 1) | Problem A | [URL] | 2026-08-05 |
| ✓ | Revival | Codeforces | Round #1105 (Div. 1) | Problem C | [URL] | 2026-08-05 |
| ✓ | Hunting the Beast | Codeforces | Round #1105 (Div. 1) | Problem D | [URL] | 2026-08-04 |
| ✓ | Aladdin And The Return Journey | LightOJ | Problem Set | 1348 | [URL] | 2014 |
| ✓ | Camelot | USACO | Training-Set | Section 3.3 | [URL] | 2014 |
| ✓ | ClosestRabbit | TopCoder | SRM 636 (Div. 1) | 500 Pt | [URL] | 2014 |
| ✓ | Compartments | Codeforces | Round #207 (Div. 1) | Problem C | [URL] | 2014 |
| ✓ | Cooking The Books | FB Hacker Cup | 2015 Qualification Round | Problem A | [URL] | 2014 |
| ✓ | Dreamoon And Strings | Codeforces | Round #272 (Div. 1) | C | [URL] | 2014 |
| ✓ | Dreamoon And Sums | Codeforces | Round #272 (Div. 1) | A | [URL] | 2014 |
| ✓ | Free Market | Codeforces | Round #213 (Div. 1) | Problem B | [URL] | 2014 |
| ✓ | Ghd | Codeforces | Round #213 (Div. 1) | D | [URL] | 2014 |
| ✓ | Jeff And Brackets | Codeforces | Round #204 (Div. 1) | C | [URL] | 2014 |
| ✓ | KitayutaMart | TopCoder | SRM 648 (Div. 1) | 550 | [URL] | 2014 |
| ✓ | Ksenia And Combinatorics | Codeforces | Round #224 (Div. 2) | Problem E | [URL] | 2014 |
| ✓ | Laser Maze | FB Hacker Cup | 2015 Qualification Round | Problem C | [URL] | 2014 |
| ✓ | Levko And Strings | Codeforces | Round #210 (Div. 1) | Problem C | [URL] | 2014 |
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