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    Maximal SquareNot Completed

    Solutions: 3181 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 3259 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 2500 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 94064 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 130668 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 147138 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 93333 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 75769 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 64509 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 54965 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 55348 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 42451 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 38602 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 8521 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3664 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 3181 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 3259 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2429 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3528 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2267 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2500 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2180 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 5763 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 147138 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 130668 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 94064 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 93333 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 75769 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 64509 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 54965 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 55348 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 42451 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 38602 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17611 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16177 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15183 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 14910 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17394 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 13940 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9062 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8258 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 13657 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10203 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 6064 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 7911 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 9011 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8405 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8342 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 7734 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8643 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6222 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4832 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6464 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 2854 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2787 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2848 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 1985 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2378 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1922 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 2008 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 1391 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 1749 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1498 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1486 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1317 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1159 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1508 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1561 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2200 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 829 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1168 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1458 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1424 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 883 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 786 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 889 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2429 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3528 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

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

    Alphabet SearchingNot Completed

    Solutions: 728 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 509 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 436 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2267 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 695 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2180 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 482 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

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

    Distinct CharactersNot Completed

    Solutions: 506 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 5763 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

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

    ASCII ConversionNot Completed

    Solutions: 409 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 556 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 487 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 605 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

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

    One DecrementedNot Completed

    Solutions: 512 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 569 | Step-by-step solution | Challenge discussion

    GCFNot Completed

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

    Serial NumberNot Completed

    Solutions: 680 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 591 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 437 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

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

    Command LineNot Completed

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

    Star RatingNot Completed

    Solutions: 874 | Step-by-step solution | Challenge discussion

    Moving MedianNot Completed

    Solutions: 295 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 602 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

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

    FizzBuzzNot Completed

    Solutions: 243 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 145 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

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

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12368 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8861 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7626 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7559 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6821 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7569 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5148 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4692 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4697 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4618 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5356 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5131 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4249 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3919 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2925 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3546 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2650 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5045 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 3023 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3469 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3211 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2934 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2485 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2922 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 386 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2394 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2726 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2435 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1521 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1672 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1537 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2461 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1544 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 885 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 755 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 498 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 752 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 376 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 323 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 194 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 259 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 442 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 280 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 472 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 266 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 471 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 149 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 120 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 374 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 185 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 329 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 202 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 141 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 289 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 89 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 267 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 94 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 291 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 241 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 115 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 68 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 251 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 76 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2500 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 167 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 200 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 272 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 128 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 124 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 109 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 364 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 171 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 169 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 242 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 120 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 83 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 157 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 561 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 429 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1302 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 312 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1213 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 803 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 382 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 139 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 589 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 8521 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 162 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 135 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 637 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 434 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 305 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 284 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 516 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 391 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 601 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 261 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 153 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 541 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 233 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 103 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 80 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 176 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 119 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 96 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 90 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 114 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 189 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 119 | 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: 238 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 118 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3664 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 158 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 166 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 139 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 204 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 389 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 3181 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 64 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 96 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 3259 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 123 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 40 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 135 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 109 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

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