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    Maximal SquareNot Completed

    Solutions: 4205 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 4254 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 3239 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 102951 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 148722 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 162589 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 104402 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 84338 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 72107 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 61359 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 61650 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 47631 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 42766 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 10115 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4346 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 4205 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 4254 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2869 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4296 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2651 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3239 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2597 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 6834 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 162589 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 148722 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 102951 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 104402 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 84338 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 72107 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 61359 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 61650 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 47631 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 42766 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17999 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16490 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15467 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 15152 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17803 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 14239 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9302 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8440 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 14047 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10408 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 6184 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 8095 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 9152 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8539 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8483 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 8136 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8787 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6390 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4944 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6611 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 3258 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2949 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2962 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 2069 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2495 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 2012 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 2105 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 1553 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 1905 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1666 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1909 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1400 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1345 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1592 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 2045 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2709 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 895 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1229 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1534 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1584 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 947 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 922 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 1028 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2869 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4296 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 916 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 782 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 592 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 468 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2651 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 761 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2597 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 530 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 900 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 534 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 6834 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 625 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 441 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 585 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 613 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 650 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

    Solutions: 626 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 554 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 618 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 599 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 743 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

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

    Palindrome SwapperNot Completed

    Solutions: 486 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 683 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 303 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

    Solutions: 994 | Step-by-step solution | Challenge discussion

    Moving MedianNot Completed

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

    Group TotalsNot Completed

    Solutions: 831 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 198 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 1404 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 201 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 213 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 13336 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8979 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7859 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7897 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6919 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7753 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5227 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4889 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4831 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4854 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5625 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5215 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4311 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3978 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2988 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3752 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2693 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5116 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 3240 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3545 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3281 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 3063 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2632 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2957 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 486 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2502 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2865 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2468 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1613 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1710 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1551 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2711 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1561 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 968 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 846 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 623 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 999 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 405 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 356 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 326 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 709 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 469 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 289 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 550 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 482 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 754 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 165 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 510 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 200 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 431 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 214 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 334 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 528 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 96 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 911 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 323 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 428 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 121 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 73 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 306 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 92 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3239 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 181 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 220 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 523 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 135 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 134 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 115 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 466 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 187 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 224 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 534 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 141 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 185 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 594 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 442 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1452 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 325 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1239 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 827 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 394 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 143 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 620 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 10115 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 176 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 157 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 751 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 453 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 358 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 287 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 655 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 403 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 620 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 298 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 163 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 548 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 240 | 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: 122 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 211 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 65 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 159 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 252 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 121 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4346 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 272 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 179 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 100 | 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: 249 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 411 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 4205 | 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: 4254 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 226 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 311 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 160 | View all user solutions | Challenge discussion

    Difficulty

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    • sequences 7
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