| #1801 | Cow DatingUSACO 2019 February Platinum | |
| #1802 | Moorio KartUSACO 2019 February Platinum | |
| #1803 | Mowing MischiefUSACO 2019 February Platinum | |
| #1804 | Academic DistancePetrozavodsk Summer 2021 Day 1 | |
| #1805 | Bunch of PaperPetrozavodsk Summer 2021 Day 1 | |
| #1806 | Character GridPetrozavodsk Summer 2021 Day 1 | |
| #1807 | Distribute the BarsPetrozavodsk Summer 2021 Day 1 | |
| #1808 | Efficient PartitioningPetrozavodsk Summer 2021 Day 1 | |
| #1809 | Find the MST for GridPetrozavodsk Summer 2021 Day 1 | |
| #1810 | Generate the SequencesPetrozavodsk Summer 2021 Day 1 | |
| #1811 | How to Move the BeansPetrozavodsk Summer 2021 Day 1 | |
| #1812 | Interesting ColoringPetrozavodsk Summer 2021 Day 1 | |
| #1813 | Joy with PermutationsPetrozavodsk Summer 2021 Day 1Interactive | |
| #1814 | Kingdoms and QuarantinePetrozavodsk Summer 2021 Day 1 | |
| #1815 | Lazy JudgePetrozavodsk Summer 2021 Day 1Interactive | |
| #1816 | Multiple ParenthesesPetrozavodsk Summer 2021 Day 1 | |
| #1817 | AND PermutationPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1818 | Apple OrchardPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1819 | Cleaning RobotPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1820 | Contest ConstructionPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1821 | Ketek CountingPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1822 | Mountainous Palindromic SubarrayPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1823 | Permutation CFGPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1824 | Special CyclePetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1825 | The King's GuardsPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1826 | The PaladinPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1827 | Token GamePetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1828 | TraveLogPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1829 | You be The Judge, AgainPetrozavodsk Summer 2021 Day 2NAC 2021 | |
| #1830 | ANDPetrozavodsk Summer 2021 Day 3 | |
| #1831 | BruteforcePetrozavodsk Summer 2021 Day 3 | |
| #1832 | Crab's CannonPetrozavodsk Summer 2021 Day 3 | |
| #1833 | DeletingPetrozavodsk Summer 2021 Day 3 | |
| #1834 | Eulerian?Petrozavodsk Summer 2021 Day 3Interactive | |
| #1835 | Fancy FormulasPetrozavodsk Summer 2021 Day 3 | |
| #1836 | Glory GraphPetrozavodsk Summer 2021 Day 3 | |
| #1837 | HamiltonianPetrozavodsk Summer 2021 Day 3 | |
| #1838 | Intellectual ImplementationPetrozavodsk Summer 2021 Day 3 | |
| #1839 | JokePetrozavodsk Summer 2021 Day 3 | |
| #1840 | K-onstructionPetrozavodsk Summer 2021 Day 3 | |
| #1841 | Little LCSPetrozavodsk Summer 2021 Day 3 | |
| #1842 | MathPetrozavodsk Summer 2021 Day 3 | |
| #1843 | Counting PairsPetrozavodsk Summer 2021 Day 4 | |
| #1844 | CactusPetrozavodsk Summer 2021 Day 4 | |
| #1845 | PermutePetrozavodsk Summer 2021 Day 4 | |
| #1846 | Nimber SequencePetrozavodsk Summer 2021 Day 4 | |
| #1847 | ElephantsPetrozavodsk Summer 2021 Day 4 | |
| #1848 | Interval ShufflePetrozavodsk Summer 2021 Day 4 | |
| #1849 | 2048 [TAG: Removed Problem]Petrozavodsk Summer 2021 Day 4 | |
| #1850 | Magic BoxPetrozavodsk Summer 2021 Day 4 | |
| #1851 | Directed Acyclic GraphPetrozavodsk Summer 2021 Day 4 | |
| #1852 | PaintPetrozavodsk Summer 2021 Day 4 | |
| #1853 | Swapping InversionsPetrozavodsk Summer 2021 Day 5 | |
| #1854 | Hamiltonian PathPetrozavodsk Summer 2021 Day 5 | |
| #1855 | Minimal Cyclic ShiftPetrozavodsk Summer 2021 Day 5 | |
| #1856 | IntervalPetrozavodsk Summer 2021 Day 5 | |
| #1857 | PlayerUnknown's BattlegroundsPetrozavodsk Summer 2021 Day 5 | |
| #1858 | SumPetrozavodsk Summer 2021 Day 5 | |
| #1859 | Reasonable Workplace RelationshipPetrozavodsk Summer 2021 Day 5 | |
| #1860 | Historic BreakthroughPetrozavodsk Summer 2021 Day 5 | |
| #1861 | Nondeterministic Finite AutomatonPetrozavodsk Summer 2021 Day 5 | |
| #1862 | Texas Hold 'emPetrozavodsk Summer 2021 Day 5 | |
| #1863 | Yes, Prime MinisterPetrozavodsk Summer 2021 Day 6 | |
| #1864 | Might and MagicPetrozavodsk Summer 2021 Day 6 | |
| #1865 | 0 TreePetrozavodsk Summer 2021 Day 6 | |
| #1866 | DecompositionPetrozavodsk Summer 2021 Day 6 | |
| #1867 | MedianPetrozavodsk Summer 2021 Day 6 | |
| #1868 | The StrugglePetrozavodsk Summer 2021 Day 6 | |
| #1869 | Power Station of ArtPetrozavodsk Summer 2021 Day 6 | |
| #1870 | Command and Conquer: Red Alert 2Petrozavodsk Summer 2021 Day 6 | |
| #1871 | Typing ContestPetrozavodsk Summer 2021 Day 6 | |
| #1872 | GamePetrozavodsk Summer 2021 Day 6 | |
| #1873 | ArrayPetrozavodsk Summer 2021 Day 6 | |
| #1874 | Goldberg Machine 2Petrozavodsk Summer 2021 Day 7 | |
| #1875 | NeinPetrozavodsk Summer 2021 Day 7 | |
| #1876 | MIPT: Connecting PeoplePetrozavodsk Summer 2021 Day 7 | |
| #1877 | Matryoshka DollsPetrozavodsk Summer 2021 Day 7 | |
| #1878 | No Rest for the WickedPetrozavodsk Summer 2021 Day 7 | |
| #1879 | The Last SamuraiPetrozavodsk Summer 2021 Day 7 | |
| #1880 | Nikanor Loves GamesPetrozavodsk Summer 2021 Day 7 | |
| #1881 | Roads of the EmpirePetrozavodsk Summer 2021 Day 7 | |
| #1882 | DrunkardsPetrozavodsk Summer 2021 Day 7 | |
| #1883 | Rational DimasikPetrozavodsk Summer 2021 Day 7 | |
| #1884 | Mission Impossible: Grand Theft AutoPetrozavodsk Summer 2021 Day 7 | |
| #1893 | Friendly RooksСПбКОШП 2021 | |
| #1894 | Guess the ArrayСПбКОШП 2021Interactive | |
| #1895 | Moving CellsСПбКОШП 2021 | |
| #1896 | Army of ClonesСПбКОШП 2021 | |
| #1897 | HaikuСПбКОШП 2021 | |
| #1898 | RaceСПбКОШП 2021 | |
| #1899 | Maximaze XOR sumСПбКОШП 2021 | |
| #1900 | Octopus GameСПбКОШП 2021 | |