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    Maximal SquareNot Completed

    Solutions: 1711 | View user solutions | Added 05/21/16

    Pentagonal NumberNot Completed

    Solutions: 1801 | View user solutions | Added 08/31/16

    Eight QueensNot Completed

    Solutions: 1399 | View user solutions | Added 11/06/16

    Free Challenges

    Longest WordNot Completed

    Solutions: 81298 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 103507 | Step-by-step solution | Challenge discussion

    First ReverseNot Completed

    Solutions: 124060 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 77334 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 62983 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 53574 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 45561 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 46105 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 35158 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 32260 | Step-by-step solution | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 5816 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 2530 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 1711 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 1801 | View all user solutions | Challenge discussion

    Correct PathNot Completed

    Solutions: 1841 | View all user solutions | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 2492 | View all user solutions | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 1605 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 1399 | View all user solutions | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 1437 | View all user solutions | Challenge discussion

    Questions MarksNot Completed

    Solutions: 4196 | View all user solutions | Challenge discussion

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    Easy Difficulty

    First ReverseNot Completed

    Solutions: 124060 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 103507 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 81298 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 77334 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 62983 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 53574 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 45561 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 46105 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 35158 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 32260 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 17167 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 15766 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 14873 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 14584 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 17000 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 13546 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 8741 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 7989 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 13243 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 9903 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 5888 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 7682 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 8725 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 8232 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 8132 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 7527 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 8415 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 6011 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4622 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 6229 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 2614 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2629 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2677 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 1835 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 2216 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1804 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 1873 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

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

    Array MatchingNot Completed

    Solutions: 1610 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 1330 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 1269 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 1219 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 1072 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1415 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 1078 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 1942 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 767 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 1098 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1382 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 1172 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 762 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 655 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 780 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 1841 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 2492 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 765 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 635 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 414 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 395 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 1605 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 609 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

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

    Number StreamNot Completed

    Solutions: 408 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

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

    Distinct CharactersNot Completed

    Solutions: 434 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 4196 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 514 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 353 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 484 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

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

    Sum MultiplierNot Completed

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

    String MergeNot Completed

    Solutions: 495 | Step-by-step solution | Challenge discussion

    One DecrementedNot Completed

    Solutions: 465 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 483 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 458 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 623 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 520 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 333 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 480 | Step-by-step solution | Challenge discussion

    Command LineNot Completed

    Solutions: 219 | Step-by-step solution | Challenge discussion

    Star RatingNot Completed

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

    Moving MedianNot Completed

    Solutions: 185 | Step-by-step solution | Challenge discussion

    Group TotalsNot Completed

    Solutions: 190 | Step-by-step solution | Challenge discussion

    String ChangesNot Completed

    Solutions: 77 | Step-by-step solution | Challenge discussion

    FizzBuzzNot Completed

    Solutions: 119 | Step-by-step solution | Challenge discussion

    H DistanceNot Completed

    Solutions: 64 | Step-by-step solution | Challenge discussion

    Different CasesNot Completed

    Solutions: 76 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 12140 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 8663 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7488 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 7192 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6681 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 7348 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 5032 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 4498 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4567 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4526 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 5197 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 5049 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 4139 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3834 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2811 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3358 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2574 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 4961 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2762 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3384 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 3142 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2863 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2366 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2858 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 296 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2323 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2666 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2374 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1440 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1632 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1497 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2419 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1502 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 755 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 674 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 460 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 471 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 339 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 297 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 162 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 203 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 305 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 240 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 433 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 207 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 378 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 100 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 166 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 160 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 265 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 160 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 159 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 78 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 161 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 70 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 122 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 179 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 97 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 58 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 202 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 57 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 1399 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 135 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 150 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 202 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 93 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 101 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 86 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 306 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 143 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 88 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 125 | View all user solutions | Challenge discussion

    PrimesNot Completed

    Solutions: 62 | View all user solutions | Challenge discussion

    String CalculateNot Completed

    Solutions: 30 | View all user solutions | Challenge discussion

    Hard Difficulty

    Sudoku Quadrant CheckerNot Completed

    Solutions: 139 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 533 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 418 | View all user solutions | Challenge discussion

    Shortest PathNot Completed

    Solutions: 1199 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 304 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1175 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 778 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 367 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 134 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 579 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 5816 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 151 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 117 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 596 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 416 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 291 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 272 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 473 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 383 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 550 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 249 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 146 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 526 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 73 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 66 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 158 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 110 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 86 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 83 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 102 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 165 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 96 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 118 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 225 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 107 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 2530 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 125 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 149 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 81 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 118 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 140 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 180 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 193 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 1711 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 49 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 48 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 1801 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 51 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 32 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 84 | View all user solutions | Challenge discussion

    Tetris MoveNot Completed

    Solutions: 41 | View all user solutions | Challenge discussion

    WildcardsNot Completed

    Solutions: 29 | View all user solutions | Challenge discussion

    Difficulty

    Companies

    • Google 44
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    Bootcamps

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    • Grace Hopper 87
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    • optimization 22
    • matrix 21
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    • sequences 7
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