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    Maximal SquareNot Completed

    Solutions: 3423 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 3491 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 2676 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 96250 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 135230 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 151026 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 96174 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 77953 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 66461 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 56629 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 56904 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 43702 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 39693 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 8940 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3840 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 3423 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 3491 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2543 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3755 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2366 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2676 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2272 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 6013 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 151026 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 135230 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 96250 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 96174 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 77953 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 66461 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 56629 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 56904 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 43702 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 39693 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17727 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16299 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15269 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 14969 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17504 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 14021 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9127 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8317 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 13780 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10264 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 6087 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 7962 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 9050 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8441 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8380 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 7768 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8684 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6315 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4878 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6520 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 3079 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2816 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2876 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 2007 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2406 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1941 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

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

    Wave SortingNot Completed

    Solutions: 1421 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 1823 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1523 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1546 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1340 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1176 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1531 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1662 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2271 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 842 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1183 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1477 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1482 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 903 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 814 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 904 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2543 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3755 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 872 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 741 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

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

    Triangle RowNot Completed

    Solutions: 443 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2366 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 715 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2272 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 493 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 809 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

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

    Questions MarksNot Completed

    Solutions: 6013 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 599 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 417 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 563 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 497 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

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

    String MergeNot Completed

    Solutions: 586 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 521 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 582 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 561 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 691 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 600 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 454 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 606 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 279 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

    Solutions: 893 | Step-by-step solution | Challenge discussion

    Moving MedianNot Completed

    Solutions: 336 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 670 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 161 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 272 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

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

    Different CasesNot Completed

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

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12437 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8888 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7639 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7666 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6841 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7608 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5164 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4740 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4770 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4638 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5420 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5157 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4271 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

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

    Counting MinutesNot Completed

    Solutions: 2948 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3639 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2653 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5058 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 3087 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3482 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3220 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2940 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2535 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2925 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 430 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2405 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2790 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2445 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1536 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1691 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1542 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2468 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1548 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 896 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 759 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 500 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 801 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 380 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 329 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 210 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 260 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 445 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 286 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 479 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 295 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 517 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 149 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 127 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 412 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 186 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 357 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 204 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 225 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 355 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 91 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 302 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 94 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 299 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 253 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 117 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 68 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 253 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 76 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2676 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 169 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 209 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 341 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 133 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 110 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 370 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 173 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 185 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 270 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 124 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 84 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 171 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 573 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 431 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1363 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 320 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1228 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 808 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 386 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 592 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 8940 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 164 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 658 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 439 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 328 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 285 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 579 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 392 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 614 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 268 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 154 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 541 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 235 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 104 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 80 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 179 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 122 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 98 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 91 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 115 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 191 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 131 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 65 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 243 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 118 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3840 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 181 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 169 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 141 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 157 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 220 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 394 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 3423 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 67 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 97 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 3491 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 149 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 40 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 154 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 132 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 93 | View all user solutions | Challenge discussion

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