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    Maximal SquareNot Completed

    Solutions: 2229 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 2344 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 1821 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 86637 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 114812 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 133490 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 83952 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 68160 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 58055 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 49386 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 49910 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 38196 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 34857 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 7002 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3034 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 2229 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 2344 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2065 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 2927 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 1896 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 1821 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 1790 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 4837 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 133490 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 114812 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 86637 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 83952 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 68160 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 58055 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 49386 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 49910 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 38196 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 34857 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17357 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 15930 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15011 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 14721 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17169 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 13695 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 8893 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

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

    Second GreatLowNot Completed

    Solutions: 13425 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10006 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 5967 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 7781 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 8815 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8308 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8233 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 7616 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8509 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6078 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4669 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6322 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 2700 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2697 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2761 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 1890 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2291 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1867 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 1939 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 1329 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

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

    Binary ReversalNot Completed

    Solutions: 1378 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1368 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1264 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1099 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1453 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1134 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2049 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 793 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1131 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1406 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1251 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 803 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 719 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 824 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2065 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 2927 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 808 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 684 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 451 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 413 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 1896 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 657 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 1790 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 445 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 634 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 470 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 4837 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 541 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 380 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 523 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

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

    Sum MultiplierNot Completed

    Solutions: 560 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

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

    One DecrementedNot Completed

    Solutions: 489 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 525 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 488 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 651 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

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

    Palindrome SwapperNot Completed

    Solutions: 361 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 525 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 247 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

    Solutions: 520 | Step-by-step solution | Challenge discussion

    Moving MedianNot Completed

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

    Group TotalsNot Completed

    Solutions: 253 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 109 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 176 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 99 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 109 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12218 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8741 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7546 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7258 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6740 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7437 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5088 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4568 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4608 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4571 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5246 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5077 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4189 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3881 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2863 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3415 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2614 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5006 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2801 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3428 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3174 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2898 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2386 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2890 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 328 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2360 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2688 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2410 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1463 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1647 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1521 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2442 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1521 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 775 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 716 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 480 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 502 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 360 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 314 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 181 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 217 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 352 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 258 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 457 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 223 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 412 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 113 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 192 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 170 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 284 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 181 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 183 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 83 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 175 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 72 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 165 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 204 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 103 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 229 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 59 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 1821 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 175 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 216 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 103 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 112 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 96 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 330 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 103 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 154 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 90 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 57 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 145 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 549 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 426 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1221 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 307 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1192 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 790 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 375 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 135 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 585 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 7002 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 155 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 123 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 609 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 425 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 298 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 277 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 489 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 385 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 556 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 253 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 151 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 532 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 182 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 79 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 75 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 166 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 111 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 93 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 86 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 108 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 174 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 108 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 61 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 127 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 226 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 112 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3034 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 134 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 84 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 125 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 147 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 191 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 204 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 2229 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 55 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 50 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 2344 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 61 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 34 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 88 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 46 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 66 | View all user solutions | Challenge discussion

    Difficulty

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