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    Maximal SquareNot Completed

    Solutions: 4234 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 4272 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 3251 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 103122 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 149044 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 162866 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 104609 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 84476 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 72233 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 61463 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 61754 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 47709 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 42832 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 10149 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4371 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 4234 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 4272 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2885 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4316 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2658 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3251 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2604 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 6849 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 162866 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 149044 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 103122 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 104609 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 84476 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 72233 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 61463 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 61754 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 47709 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 42832 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 18002 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16496 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15468 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 15154 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17809 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 14241 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9305 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

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

    Second GreatLowNot Completed

    Solutions: 14051 | 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: 8106 | 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: 8486 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 8137 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8790 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6395 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4945 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6612 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 3260 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2952 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2964 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 2070 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

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

    Bitwise OneNot Completed

    Solutions: 2013 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 2106 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 1554 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

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

    Binary ReversalNot Completed

    Solutions: 1673 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1914 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1402 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1348 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1595 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 2056 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2713 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 897 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1233 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1535 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1586 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

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

    Food DistributionNot Completed

    Solutions: 925 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 1029 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2885 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4316 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 918 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

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

    Time DifferenceNot Completed

    Solutions: 594 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

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

    Vowel SquareNot Completed

    Solutions: 2658 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 762 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2604 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

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

    Largest FourNot Completed

    Solutions: 906 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

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

    Questions MarksNot Completed

    Solutions: 6849 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 628 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

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

    Simple EvensNot Completed

    Solutions: 587 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 620 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 653 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

    Solutions: 628 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 557 | 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: 745 | 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: 684 | 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: 475 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 835 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

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

    FizzBuzzNot Completed

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

    H DistanceNot Completed

    Solutions: 203 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 215 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 13344 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8981 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

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

    Palindrome TwoNot Completed

    Solutions: 7901 | 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: 4891 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4834 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4855 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5626 | 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: 3753 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2697 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5117 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 3244 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3548 | 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: 2636 | 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: 2510 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2874 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2470 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1621 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1713 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1556 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2712 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1565 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 979 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 847 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 629 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 1005 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 406 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 363 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 328 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 710 | 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: 556 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 489 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 767 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 165 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 151 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 511 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 200 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 433 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 214 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 335 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 533 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 96 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 917 | 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: 432 | 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: 319 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 92 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3251 | 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: 527 | 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: 467 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 187 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 228 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 538 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 141 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 133 | 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: 1455 | 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: 10149 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 176 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 158 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 771 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 454 | 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: 157 | 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: 4371 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 277 | 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: 254 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 411 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 4234 | 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: 4272 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 229 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 317 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 166 | View all user solutions | Challenge discussion

    Difficulty

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    • matrix 21
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    • algebra 10
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    • sequences 7
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