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    Maximal SquareNot Completed

    Solutions: 2176 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 2283 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 1790 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 86056 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 113637 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 132534 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 83260 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 67634 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 57572 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 49011 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 49521 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 37876 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 34593 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 6893 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 2992 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 2176 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 2283 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 2049 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 2874 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 1879 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 1790 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 1741 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 4790 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 132534 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 113637 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 86056 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 83260 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 67634 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 57572 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 49011 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 49521 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 37876 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 34593 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17317 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 15897 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 14988 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 14702 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17143 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 13682 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 8878 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 8083 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 13403 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 9994 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 5958 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

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

    Dash InsertNot Completed

    Solutions: 8801 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8300 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8222 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 7603 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8491 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6070 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4657 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6301 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 2690 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2689 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2750 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 1887 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2288 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1863 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 1933 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 1325 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 1676 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1374 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1357 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1259 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1094 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1449 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1125 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 2039 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 791 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1128 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1401 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1240 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 798 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 716 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 813 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 2049 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 2874 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 806 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 683 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 448 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 413 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 1879 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 648 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 1741 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 444 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 630 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 467 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 4790 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 540 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 380 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

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

    Snake CaseNot Completed

    Solutions: 446 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 557 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

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

    One DecrementedNot Completed

    Solutions: 488 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 524 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 486 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 648 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 554 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 361 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 523 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 247 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

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

    Moving MedianNot Completed

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

    Group TotalsNot Completed

    Solutions: 246 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 105 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 172 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 98 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 107 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12208 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8737 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7541 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7252 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6733 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7419 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5078 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4553 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

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

    Letter CountNot Completed

    Solutions: 4563 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5236 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5071 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4179 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3875 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2851 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3400 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2608 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 4999 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2795 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3422 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3164 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2891 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2381 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2884 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 323 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2354 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2684 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2402 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1456 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1644 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1514 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2436 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1519 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 772 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 715 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 476 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 499 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 360 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 314 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 181 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 217 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 325 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 258 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 457 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 223 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 409 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 113 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 190 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 168 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 282 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 180 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 91 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 176 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 83 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 175 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 72 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 141 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 203 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 103 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 229 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 59 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 1790 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 149 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 171 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 213 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 102 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 112 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 96 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 328 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 101 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 151 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 88 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 55 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 143 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 547 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 425 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1219 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 307 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1192 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 790 | 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: 585 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 6893 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 155 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 123 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 606 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 423 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 298 | 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: 385 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 556 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 252 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 151 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 532 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 163 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 79 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 73 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 164 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 110 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 91 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 85 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 108 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 174 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 106 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 127 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 226 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 112 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 2992 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 132 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 82 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 125 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 147 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 191 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 203 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 2176 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 55 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 50 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 2283 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 58 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 34 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 46 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 61 | View all user solutions | Challenge discussion

    Difficulty

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