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    Maximal SquareNot Completed

    Solutions: 2794 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 2897 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 2245 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 91136 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 124457 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 141816 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 89535 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 72758 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 61900 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 52739 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 53173 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 40746 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 37089 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 7953 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3427 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 2794 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 2897 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2304 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3255 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2125 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2245 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2037 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 5425 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 141816 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 124457 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 91136 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 89535 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 72758 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 61900 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 52739 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 53173 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 40746 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 37089 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17485 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16057 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15111 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 14836 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17288 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 13827 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9000 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8205 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 13577 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10115 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 6028 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 7869 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 8960 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8368 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8287 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 7688 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8597 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6138 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4724 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6377 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 2748 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2742 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2804 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 1960 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2344 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1897 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 1984 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 1361 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 1726 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1454 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1435 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1298 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1136 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1485 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1239 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2110 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 816 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1153 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1435 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1375 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

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

    Food DistributionNot Completed

    Solutions: 739 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 860 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2304 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3255 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 832 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 713 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

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

    Triangle RowNot Completed

    Solutions: 425 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2125 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 675 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2037 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 460 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 769 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 494 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 5425 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 574 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 396 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

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

    Snake CaseNot Completed

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

    Sum MultiplierNot Completed

    Solutions: 578 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

    Solutions: 555 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 507 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 552 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 532 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 671 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 578 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 397 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

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

    Command LineNot Completed

    Solutions: 263 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

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

    Moving MedianNot Completed

    Solutions: 241 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 339 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 135 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 220 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 136 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

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

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12295 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8804 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7596 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7317 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6782 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7514 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5115 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4650 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4632 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4600 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5296 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5105 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4233 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3904 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2897 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3442 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2634 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5037 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2820 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3456 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3199 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2911 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2456 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2906 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 367 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2383 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2710 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2424 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1519 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1664 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1530 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2451 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1537 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 865 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 737 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 491 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 544 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 364 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 318 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 184 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 244 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 420 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 272 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 469 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 257 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 460 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 146 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 117 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 213 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 182 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 306 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 198 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 112 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 226 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 189 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 83 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 266 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 235 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 114 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 63 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 248 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 72 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2245 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 166 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 199 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 255 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 128 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 121 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 108 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 359 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 169 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 157 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 207 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 109 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 75 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 556 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 427 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1292 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 310 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1204 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 796 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 379 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 136 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 588 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 7953 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 160 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 129 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 616 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 429 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 301 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 280 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 490 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 389 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 599 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 258 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 152 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 540 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 232 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 102 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 77 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 174 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 117 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 94 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 88 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 112 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 181 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 116 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 64 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 134 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 233 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 114 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3427 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 152 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 162 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 86 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 137 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 154 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 197 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 213 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 2794 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 58 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 55 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 2897 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 92 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 35 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 120 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 65 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 78 | View all user solutions | Challenge discussion

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