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    Remove BracketsNot Completed

    Solutions: 46 | View user solutions | Added 08/23/17

    Plus MinusNot Completed

    Solutions: 36 | View user solutions | Added 08/04/17

    Wildcard CharactersNot Completed

    Solutions: 26 | View user solutions | Added 07/22/17

    You have access to 10 free challenges and solutions below

    Easy Difficulty

    First ReverseNot Completed

    Solutions: 80350 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 55289 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 42166 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 44502 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 36952 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 31441 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 25073 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 26627 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 20128 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 18926 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 15526 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 14595 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 13773 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 13336 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 15479 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 12241 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 7647 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 7017 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 11782 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 8857 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 5213 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 6938 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 7827 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 7556 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 7286 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 6760 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 7636 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 5280 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 4117 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 5506 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 1975 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 2003 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 2009 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 1359 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 1648 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 1341 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

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

    Wave SortingNot Completed

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

    Array MatchingNot Completed

    Solutions: 974 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 836 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

    Solutions: 783 | Step-by-step solution | Challenge discussion

    Even PairsNot Completed

    Solutions: 751 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 677 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 1009 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 688 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 1191 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 476 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 774 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 1017 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

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

    Basic Roman NumeralsNot Completed

    Solutions: 502 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

    Solutions: 378 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

    Solutions: 472 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 244 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 406 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 401 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 379 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

    Solutions: 216 | Step-by-step solution | Challenge discussion

    Triangle RowNot Completed

    Solutions: 218 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 260 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 315 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 155 | Step-by-step solution | Challenge discussion

    Number StreamNot Completed

    Solutions: 179 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 326 | Step-by-step solution | Challenge discussion

    Distinct CharactersNot Completed

    Solutions: 222 | Step-by-step solution | Challenge discussion

    Questions MarksNot Completed

    Solutions: 332 | Step-by-step solution | Challenge discussion

    Camel CaseNot Completed

    Solutions: 242 | Step-by-step solution | Challenge discussion

    ASCII ConversionNot Completed

    Solutions: 162 | Step-by-step solution | Challenge discussion

    Simple EvensNot Completed

    Solutions: 241 | Step-by-step solution | Challenge discussion

    Snake CaseNot Completed

    Solutions: 208 | Step-by-step solution | Challenge discussion

    Sum MultiplierNot Completed

    Solutions: 276 | Step-by-step solution | Challenge discussion

    String MergeNot Completed

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

    One DecrementedNot Completed

    Solutions: 242 | Step-by-step solution | Challenge discussion

    Element MergerNot Completed

    Solutions: 261 | Step-by-step solution | Challenge discussion

    GCFNot Completed

    Solutions: 232 | Step-by-step solution | Challenge discussion

    Serial NumberNot Completed

    Solutions: 223 | Step-by-step solution | Challenge discussion

    String PeriodsNot Completed

    Solutions: 188 | Step-by-step solution | Challenge discussion

    Palindrome SwapperNot Completed

    Solutions: 106 | Step-by-step solution | Challenge discussion

    Remove BracketsNot Completed

    Solutions: 46 | Step-by-step solution | Challenge discussion

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    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 11403 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 7935 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 7052 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 6644 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 6238 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 6729 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 4684 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 3960 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4277 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 4102 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 4663 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 4724 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3516 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 3819 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2548 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 3039 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2314 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 4600 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2532 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 3080 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 2878 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2634 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2176 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 2130 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2638 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2479 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 2126 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1298 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1474 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2237 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1329 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1366 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 584 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 487 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 322 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 312 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 232 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 197 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 178 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 102 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 119 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 105 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 155 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 305 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 248 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 76 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 54 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 89 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 97 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 156 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 93 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 56 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 82 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 40 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 41 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 61 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 99 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 52 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 31 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 111 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 26 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 49 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 69 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 79 | View all user solutions | Challenge discussion

    Simple PasswordNot Completed

    Solutions: 111 | View all user solutions | Challenge discussion

    Preorder TraversalNot Completed

    Solutions: 43 | View all user solutions | Challenge discussion

    String ZigzagNot Completed

    Solutions: 56 | View all user solutions | Challenge discussion

    Off BinaryNot Completed

    Solutions: 48 | View all user solutions | Challenge discussion

    Longest ConsecutiveNot Completed

    Solutions: 188 | View all user solutions | Challenge discussion

    String ExpressionNot Completed

    Solutions: 88 | View all user solutions | Challenge discussion

    Charlie the DogNot Completed

    Solutions: 26 | View all user solutions | Challenge discussion

    Plus MinusNot Completed

    Solutions: 36 | View all user solutions | Challenge discussion

    Hard Difficulty

    Shortest PathNot Completed

    Solutions: 1016 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 665 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1078 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 325 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 525 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 113 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 270 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 533 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 371 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 263 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 245 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 423 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 353 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 473 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 399 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 228 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 497 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 49 | View all user solutions | Challenge discussion

    Sudoku Quadrant CheckerNot Completed

    Solutions: 96 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 42 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 123 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 66 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 51 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 54 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 64 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 101 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 59 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 42 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 137 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 478 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 92 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 127 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 131 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 82 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 80 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 196 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 80 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 48 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 113 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 61 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 89 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 143 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 94 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 121 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 33 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 29 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 25 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 32 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 24 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 19 | View all user solutions | Challenge discussion

    Wildcard CharactersNot Completed

    Solutions: 26 | View all user solutions | Challenge discussion

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    • stack 7
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    • chess 5
    • encoding 5
    • binary tree 5
    • linear algebra 4
    • geometry 4
    • character codes 3
    • set theory 3
    • prime numbers 3
    • heap 3
    • bitwise operation 2
    • cache 1