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    String PeriodsNot Completed

    Solutions: 30 | View user solutions | Added 05/14/17

    Charlie the DogNot Completed

    Solutions: 15 | View user solutions | Added 05/13/17

    Serial NumberNot Completed

    Solutions: 101 | View user solutions | Added 04/12/17

    You have access to 10 free challenges and solutions below

    Easy Difficulty

    First ReverseNot Completed

    Solutions: 71392 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 49423 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 38657 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 39104 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 33042 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 28178 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 22097 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 23872 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 17957 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 16944 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 14843 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 14089 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 13297 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 12814 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 14859 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 11674 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 7266 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 6634 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 11248 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 8442 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 4983 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 6631 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 7425 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 7218 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 6976 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 6473 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 7250 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 5003 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 3917 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 5206 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 1729 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 1752 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 1707 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 1164 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 1415 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1162 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 1000 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 678 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 758 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 692 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

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

    Even PairsNot Completed

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

    Next PalindromeNot Completed

    Solutions: 527 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 755 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 547 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 923 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 369 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 564 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 752 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 536 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 382 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 313 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 364 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 199 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 291 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 280 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 277 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 147 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 147 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 177 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 204 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 77 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 207 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 128 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 159 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 146 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 97 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 151 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 127 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 165 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

    Solutions: 149 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 133 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 153 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 129 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 101 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 30 | Step-by-step solution | Challenge discussion

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    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 11026 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 7661 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 6868 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 6427 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 5930 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 6454 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 4534 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 3791 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4172 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 3932 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 4422 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 4552 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3375 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 3695 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2471 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 2912 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2227 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 4455 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2424 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 2963 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 2766 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2542 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2100 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2050 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2552 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2402 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2035 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1257 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1422 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2164 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1268 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1301 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 523 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 415 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 276 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 271 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 171 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 157 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 149 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 78 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 90 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 85 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 130 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 237 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 108 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 195 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 58 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 43 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 68 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 75 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 124 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 78 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 48 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 32 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 74 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 31 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 49 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 66 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 36 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 21 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 79 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 17 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 36 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 59 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 55 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 73 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 25 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 38 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 32 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 143 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 51 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 15 | View all user solutions | Challenge discussion

    Hard Difficulty

    Shortest PathNot Completed

    Solutions: 962 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 628 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1052 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 321 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 520 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 111 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 266 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 518 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 365 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 259 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 243 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 414 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 350 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 466 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 397 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 223 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 489 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 46 | View all user solutions | Challenge discussion

    Sudoku Quadrant CheckerNot Completed

    Solutions: 93 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 40 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 112 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 63 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 48 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 52 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 58 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 91 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 55 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 39 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 134 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 476 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 85 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 124 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 129 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 73 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 73 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 185 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 76 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 44 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 85 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 101 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 55 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 79 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 88 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 111 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 30 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 27 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 20 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 25 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 20 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 14 | View all user solutions | Challenge discussion