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    Maximal SquareNot Completed

    Solutions: 2533 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 2626 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 2037 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 88935 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 119688 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 137626 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 86730 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 70432 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 59982 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 51040 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 51499 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 39410 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 35948 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 7458 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3226 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 2533 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 2626 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2166 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3087 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2013 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2037 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 1918 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 5120 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 137626 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 119688 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 88935 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 86730 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 70432 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 59982 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 51040 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 51499 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 39410 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 35948 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17420 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16000 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15057 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 14772 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17224 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 13760 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 8950 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8156 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 13496 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10058 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 5999 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 7826 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 8919 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8335 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8253 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 7642 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8543 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6107 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4690 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6343 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 2721 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2711 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2777 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 1910 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2307 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1880 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 1959 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

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

    Array MatchingNot Completed

    Solutions: 1706 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1437 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1381 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1281 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1112 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1470 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1157 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2069 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 801 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1139 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1422 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1293 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 855 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 724 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 837 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2166 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3087 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 815 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 692 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

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

    Triangle RowNot Completed

    Solutions: 416 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2013 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 667 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

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

    Number StreamNot Completed

    Solutions: 452 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 732 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 479 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 5120 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

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

    ASCII ConversionNot Completed

    Solutions: 386 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 528 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 461 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 568 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

    Solutions: 542 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 496 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 535 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 499 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 662 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

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

    Palindrome SwapperNot Completed

    Solutions: 371 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 535 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 250 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

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

    Moving MedianNot Completed

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

    Group TotalsNot Completed

    Solutions: 281 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 116 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 191 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 113 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 123 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12256 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8769 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7571 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7279 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6758 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7472 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5101 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4592 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

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

    Letter CountNot Completed

    Solutions: 4582 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5270 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

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

    ConsecutiveNot Completed

    Solutions: 4219 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3890 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2874 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3425 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2619 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5011 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2804 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3434 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3179 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2902 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2403 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2897 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 340 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2363 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2698 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2415 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1505 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1649 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1523 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2445 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1528 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 844 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 728 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 487 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 509 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 362 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 315 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 183 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 226 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 418 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 267 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 465 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 244 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 450 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 144 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 116 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 203 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 174 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 294 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 188 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 205 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 86 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 178 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 81 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 261 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 226 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 108 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 62 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 236 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 68 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2037 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 157 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 177 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 243 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 106 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 115 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 99 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 343 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 154 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 127 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 189 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 98 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 63 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 147 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 551 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 426 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1266 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 309 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1199 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 791 | 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: 586 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 7458 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 158 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 125 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 610 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 427 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 299 | 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: 387 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 591 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 257 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 151 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 533 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 231 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 75 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 171 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 112 | 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: 111 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 178 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 108 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 62 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 127 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 227 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 113 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 3226 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 144 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 159 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 84 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 130 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 194 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 208 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 2533 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 55 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 54 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 2626 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 75 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 34 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 110 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 50 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 68 | View all user solutions | Challenge discussion

    Difficulty

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