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    Maximal SquareNot Completed

    Solutions: 4568 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 4609 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 3492 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 105815 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 154263 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 167159 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 107468 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 86939 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 74317 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 63253 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 63588 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 49124 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 44055 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 10586 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4584 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 4568 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 4609 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 3058 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4515 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2769 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3492 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2738 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 7208 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 167159 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 154263 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 105815 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 107468 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 86939 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 74317 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 63253 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 63588 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 49124 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 44055 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 18123 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16576 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15528 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 15244 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17996 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 14292 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9367 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8495 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 14185 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10439 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 6203 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 8180 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 9184 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8561 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8514 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 8168 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8821 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6413 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4961 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6632 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 3288 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2974 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2983 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 2088 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2508 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 2021 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 2131 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

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

    Array MatchingNot Completed

    Solutions: 1929 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

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

    Longest Increasing SequenceNot Completed

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

    Even PairsNot Completed

    Solutions: 1409 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1360 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1609 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 2189 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2883 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 907 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1241 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1542 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1649 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 963 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

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

    Three SumNot Completed

    Solutions: 1114 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 3058 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 4515 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

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

    Alphabet SearchingNot Completed

    Solutions: 841 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 614 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

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

    Vowel SquareNot Completed

    Solutions: 2769 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 948 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2738 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 577 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 995 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 545 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 7208 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 659 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 447 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

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

    Snake CaseNot Completed

    Solutions: 679 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 790 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

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

    One DecrementedNot Completed

    Solutions: 583 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 624 | Step-by-step solution | Challenge discussion

    GCFNot Completed

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

    Serial NumberNot Completed

    Solutions: 757 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

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

    Palindrome SwapperNot Completed

    Solutions: 495 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 854 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

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

    Star RatingNot Completed

    Solutions: 1127 | Step-by-step solution | Challenge discussion

    Moving MedianNot Completed

    Solutions: 538 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 1024 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

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

    FizzBuzzNot Completed

    Solutions: 1918 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 232 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 255 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 13753 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 9028 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

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

    Palindrome TwoNot Completed

    Solutions: 7936 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6970 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

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

    Arith Geo IINot Completed

    Solutions: 5247 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4932 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4865 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4927 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5691 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5230 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4328 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 4004 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 3001 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3857 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2718 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5126 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 3255 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3553 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3287 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 3115 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2701 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 3002 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 491 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2618 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2911 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2475 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1645 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1719 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1561 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2717 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1644 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 1032 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 931 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 664 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 1044 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 419 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 430 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 344 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 1009 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 506 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 300 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 598 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 597 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 1097 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 175 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 162 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 524 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 204 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 458 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 256 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 344 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 739 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 104 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 1191 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 347 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 573 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 124 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 74 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 333 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 101 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 3492 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 191 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 225 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 639 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 139 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 119 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 486 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 191 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 263 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 612 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 232 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 195 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 599 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 443 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1518 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 330 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1267 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 832 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 398 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 143 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 622 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 10586 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 179 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 205 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 905 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 485 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 411 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 289 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 665 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 403 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 635 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 313 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 165 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 548 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 244 | 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: 139 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 231 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 198 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 65 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 173 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 253 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 121 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4584 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 390 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 189 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 117 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 148 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 166 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 342 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 428 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 4568 | 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: 4609 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 321 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 411 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 159 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 192 | View all user solutions | Challenge discussion

    Difficulty

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