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    Maximal SquareNot Completed

    Solutions: 3903 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 3960 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 3050 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 100439 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 143620 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 158274 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 101259 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 81997 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 70037 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 59598 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 59915 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 46351 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 41624 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 9660 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4158 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 3903 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 3960 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2747 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4086 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2548 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3050 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2486 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 6547 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 158274 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 143620 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 100439 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 101259 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 81997 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 70037 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 59598 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 59915 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 46351 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 41624 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17908 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16413 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15413 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 15087 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17695 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 14160 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9230 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8397 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 13934 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10359 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 6154 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 8024 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 9112 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8499 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8443 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 8100 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8745 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6367 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4917 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6578 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 3219 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2913 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2930 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 2048 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2463 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1983 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 2086 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 1459 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 1886 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1652 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1674 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1386 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1327 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1567 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1964 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2641 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 874 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1209 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1517 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1540 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

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

    Food DistributionNot Completed

    Solutions: 870 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 949 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2747 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4086 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 896 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 767 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 565 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 457 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2548 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 738 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2486 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 513 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 862 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 526 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 6547 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 617 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 430 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 575 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 559 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 636 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

    Solutions: 602 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 540 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 608 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 580 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 725 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 605 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 478 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 637 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 287 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

    Solutions: 959 | Step-by-step solution | Challenge discussion

    Moving MedianNot Completed

    Solutions: 411 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 775 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 184 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 890 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 174 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 197 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12910 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8948 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7687 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7820 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6878 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7704 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5190 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4798 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4799 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4698 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5522 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5190 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4291 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3952 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2970 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3711 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2665 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5081 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 3209 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3506 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3239 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2959 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2568 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2935 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 454 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2426 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2822 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2453 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1575 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1700 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1546 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2696 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1556 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 938 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 831 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 515 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 935 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 395 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 339 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 235 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 395 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 458 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 289 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 500 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 396 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 599 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 155 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 491 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 191 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 390 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 211 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 313 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 417 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 94 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 638 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 94 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 311 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 315 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 118 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 71 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 256 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 76 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3050 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 179 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 214 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 400 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 135 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 130 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 114 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 422 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 182 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 209 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 353 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 134 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 92 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 179 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 588 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 441 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1392 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 321 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1229 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 820 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 390 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 610 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 9660 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 173 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 685 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 440 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 344 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 285 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 645 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 398 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 616 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 284 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 163 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 547 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 240 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 104 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 83 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 190 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 136 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 100 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 120 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 206 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 137 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 65 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 149 | 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: 4158 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 201 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 176 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 89 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 146 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 164 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 232 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 407 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 3903 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 76 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 98 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 3960 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 178 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 45 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 228 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 105 | View all user solutions | Challenge discussion

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