| #604 | Sum 6 | |
| #605 | Alternating permutation | |
| #663 | Spanning TreesPetrozavodsk Winter 2017 Day 3 | |
| #664 | TrianglePetrozavodsk Winter 2017 Day 3 | |
| #665 | Boxes and BallsPetrozavodsk Winter 2017 Day 3 | |
| #666 | Bit OperationsPetrozavodsk Winter 2017 Day 3 | |
| #667 | Randomized Binary Search TreePetrozavodsk Winter 2017 Day 3 | |
| #668 | ElectionPetrozavodsk Winter 2017 Day 3 | |
| #669 | HashPetrozavodsk Winter 2017 Day 3 | |
| #670 | K-th StringPetrozavodsk Winter 2017 Day 3 | |
| #671 | Shortest Path QueriesPetrozavodsk Winter 2017 Day 3 | |
| #672 | Kitamasa's CounterattackPetrozavodsk Winter 2017 Day 3 | |
| #673 | WrappingPetrozavodsk Winter 2017 Day 3 | |
| #674 | Ascending TreePetrozavodsk Winter 2017 Day 3 | |
| #675 | Land of the Rainbow GoldAPIO 2017 | |
| #676 | Travelling MerchantAPIO 2017 | |
| #677 | Koala GameAPIO 2017Interactive | |
| #678 | Honeycomb problemBaltic OI 2000 | |
| #679 | Time ZonesBaltic OI 2000 | |
| #680 | Electronical plateBaltic OI 2000 | |
| #681 | Division expressionBaltic OI 2000 | |
| #682 | StickersBaltic OI 2000 | |
| #683 | MutexesBaltic OI 2000 | |
| #685 | Y-Shaped KnifePetrozavodsk Winter 2020 Day 4 | |
| #686 | Bad DoctorPetrozavodsk Winter 2020 Day 4 | |
| #687 | Topological OrderingPetrozavodsk Winter 2020 Day 4 | |
| #688 | Bracket Euler TourPetrozavodsk Winter 2020 Day 4 | |
| #689 | Tree of ChargePetrozavodsk Winter 2020 Day 4 | |
| #690 | Find a TreePetrozavodsk Winter 2020 Day 4 | |
| #691 | One RootPetrozavodsk Winter 2020 Day 4 | |
| #692 | Delete the PointsPetrozavodsk Winter 2020 Day 4 | |
| #693 | Hard Times for Your DataPetrozavodsk Winter 2020 Day 4 | |
| #694 | ProgramPetrozavodsk Winter 2020 Day 4 | |
| #695 | Equation Mod 3 | |
| #696 | AI JeopardyKTH Challenge 2020 | |
| #697 | BlingKTH Challenge 2020 | |
| #698 | Friendly FireKTH Challenge 2020 | |
| #699 | GaggleKTH Challenge 2020 | |
| #700 | Pitch PerformanceKTH Challenge 2020 | |