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    Maximal SquareNot Completed

    Solutions: 3677 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 3739 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 2879 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 98411 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 139715 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 154787 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 98857 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 80094 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 68357 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 58145 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 58482 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 44925 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 40737 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 9322 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 4002 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 3677 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 3739 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2636 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3911 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2460 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2879 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2377 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 6276 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 154787 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 139715 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 98411 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 98857 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 80094 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 68357 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 58145 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 58482 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 44925 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 40737 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17811 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 16350 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 15313 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 15012 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17605 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 14089 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 9188 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8360 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 13856 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 10310 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 6127 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 7998 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 9082 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8474 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8413 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 7798 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8716 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

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

    Multiplicative PersistenceNot Completed

    Solutions: 4899 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6547 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 3194 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2882 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2903 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 2028 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2435 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1964 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

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

    Wave SortingNot Completed

    Solutions: 1443 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 1855 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1569 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1631 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1358 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1188 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1548 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1798 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2309 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 858 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1197 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1499 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1507 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 918 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 851 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 919 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2636 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 3911 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 884 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 749 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 551 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 449 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 2460 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 731 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 2377 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 504 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 839 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 519 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 6276 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

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

    ASCII ConversionNot Completed

    Solutions: 423 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

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

    Snake CaseNot Completed

    Solutions: 537 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 625 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

    Solutions: 595 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 527 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 588 | Step-by-step solution | Challenge discussion

    GCFNot Completed

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

    Serial NumberNot Completed

    Solutions: 702 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 601 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 469 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 627 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 284 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

    Solutions: 927 | Step-by-step solution | Challenge discussion

    Moving MedianNot Completed

    Solutions: 394 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 721 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

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

    FizzBuzzNot Completed

    Solutions: 439 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 167 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 183 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12556 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8916 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

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

    Palindrome TwoNot Completed

    Solutions: 7778 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6856 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7657 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5176 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

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

    Binary ConverterNot Completed

    Solutions: 4779 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4673 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5472 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5182 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4283 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3945 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2963 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3691 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2657 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 5071 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 3179 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3498 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3232 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2956 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2559 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2932 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 447 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2422 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2812 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2449 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1564 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1697 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1544 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2562 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1551 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 931 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 804 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 507 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 890 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 385 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 338 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 221 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 265 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 450 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 288 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 488 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 359 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 574 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 154 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 137 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 468 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 189 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 365 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 206 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 305 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 378 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 92 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 392 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 94 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 303 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 292 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 117 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 71 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 254 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 76 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 2879 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 178 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 211 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 384 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 134 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 113 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 395 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 181 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 197 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 307 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 127 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 176 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 583 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 434 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1380 | 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: 814 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 387 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 600 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 9322 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 169 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 143 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 670 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 439 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 337 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 285 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 644 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 394 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 615 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 276 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 154 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 546 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 240 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 104 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 83 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 180 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 133 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 99 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 91 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 116 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 194 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 137 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 65 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 144 | 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: 4002 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 189 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 171 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 88 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 145 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 163 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 223 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 397 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 3677 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 70 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 98 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 3739 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 163 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 40 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 207 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 104 | View all user solutions | Challenge discussion

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