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    Maximal SquareNot Completed

    Solutions: 4502 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 4571 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 3437 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 105347 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 153325 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 166395 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 107029 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 86502 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 73958 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 62917 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 63259 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 48884 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 43829 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 10510 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4559 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 4502 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 4571 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 3019 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4495 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2755 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3437 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2720 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 7143 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 166395 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 153325 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 105347 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 107029 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 86502 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 73958 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 62917 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 63259 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 48884 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 43829 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 18110 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16564 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15518 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 15218 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17966 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 14283 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9355 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8475 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 14175 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10437 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 6196 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 8174 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 9172 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8555 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8512 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 8162 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8816 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6410 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4958 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6628 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 3285 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2969 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2981 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 2085 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2506 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 2020 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 2129 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 1559 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 1927 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1681 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1951 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1408 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1357 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1608 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 2097 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2858 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 903 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1240 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1541 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1642 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 960 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 943 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 1073 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 3019 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4495 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 927 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 829 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 612 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 473 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2755 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 910 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2720 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 571 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 992 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 544 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 7143 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 655 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 445 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 591 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 668 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 774 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

    Solutions: 635 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 571 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 623 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 607 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 751 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 642 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 494 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 823 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 308 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

    Solutions: 1070 | Step-by-step solution | Challenge discussion

    Moving MedianNot Completed

    Solutions: 535 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 960 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 209 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 1796 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 227 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 250 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 13661 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 9016 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7891 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7929 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6962 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7791 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5245 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4924 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4862 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4895 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5688 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5229 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4326 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 4003 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2999 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3814 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2718 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5126 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 3252 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3553 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3287 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 3083 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2691 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2993 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 489 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2611 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2908 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2475 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1643 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1719 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1560 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2717 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1600 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 1023 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 900 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 655 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 1040 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 414 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 429 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 344 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 940 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 496 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 300 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 585 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 562 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 979 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 174 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 161 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 524 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 204 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 457 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 255 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 344 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 632 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 104 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 1118 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 347 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 497 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 124 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 74 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 333 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 100 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3437 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 191 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 225 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 611 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 139 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 118 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 484 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 189 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 250 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 596 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 154 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 226 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 190 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 598 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 442 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1507 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 330 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1265 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 831 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 398 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 143 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 622 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 10510 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 179 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 189 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 891 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 477 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 400 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 289 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 658 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 403 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 629 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 304 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 164 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 548 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 241 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 105 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 83 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 191 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 136 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 103 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 137 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 221 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 194 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 65 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 173 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 253 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 121 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4559 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 314 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 185 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 117 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 147 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 166 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 341 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 427 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 4502 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 79 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 106 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 4571 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 309 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 376 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 159 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 185 | View all user solutions | Challenge discussion

    Difficulty

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