• Challenges
  • Algorithms
  • Recently Added

    Scale BalancingNot Completed

    Solutions: 23 | View user solutions | Added 09/20/16

    Correct PathNot Completed

    Solutions: 19 | View user solutions | Added 09/16/16

    Histogram AreaNot Completed

    Solutions: 13 | View user solutions | Added 09/13/16

    You have access to 10 free challenges and solutions below

    Easy Difficulty

    First ReverseNot Completed

    Solutions: 54550 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 38214 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 31910 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 29165 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 25824 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 22056 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 16266 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 18509 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 13804 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 13154 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 13207 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 12854 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 12234 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 11510 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 13247 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 10155 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 6225 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 5643 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 9802 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 7451 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 4390 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 5891 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 6410 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 6450 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 6235 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 5744 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 6300 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 4300 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 3426 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 4481 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 1108 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 1119 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

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

    Hamming DistanceNot Completed

    Solutions: 739 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 872 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 771 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 285 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 238 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 269 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

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

    Longest Increasing SequenceNot Completed

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

    Even PairsNot Completed

    Solutions: 202 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 177 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

    Solutions: 189 | Step-by-step solution | Challenge discussion

    Nonrepeating CharacterNot Completed

    Solutions: 197 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 299 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 117 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 129 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

    Solutions: 177 | Step-by-step solution | Challenge discussion

    Palindrome CreatorNot Completed

    Solutions: 160 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

    Solutions: 149 | Step-by-step solution | Challenge discussion

    Food DistributionNot Completed

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

    Three SumNot Completed

    Solutions: 79 | Step-by-step solution | Challenge discussion

    Correct PathNot Completed

    Solutions: 19 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 23 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 10222 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 7059 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 6448 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 5929 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 5311 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 5866 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 4216 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 3419 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

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

    Letter CountNot Completed

    Solutions: 3550 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 3879 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 4178 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3065 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 3411 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2280 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 2623 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2002 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 4137 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2230 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 2696 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 2493 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2322 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 1936 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 1870 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2353 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2199 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 1846 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1182 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1335 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2012 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1149 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1190 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 390 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 266 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 173 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 163 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 92 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 98 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 99 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 48 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 29 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 34 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 56 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 95 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 42 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 71 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 24 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 20 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 20 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 32 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 43 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 33 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 24 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 19 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 14 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 18 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 16 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 13 | View all user solutions | Challenge discussion

    Hard Difficulty

    Shortest PathNot Completed

    Solutions: 861 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 568 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 979 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 296 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 482 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 102 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 257 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 480 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 339 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 241 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 232 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 392 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 338 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 442 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 395 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 220 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 474 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 44 | View all user solutions | Challenge discussion

    Sudoku Quadrant CheckerNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 37 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 86 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 61 | View all user solutions | Challenge discussion

    Array JumpingNot Completed

    Solutions: 45 | View all user solutions | Challenge discussion

    Matrix BorderNot Completed

    Solutions: 50 | View all user solutions | Challenge discussion

    Roman Numeral ReductionNot Completed

    Solutions: 53 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 69 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 43 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 33 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 129 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 471 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 72 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 122 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 123 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 59 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 60 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 178 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 62 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 39 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 71 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 85 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 40 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 58 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 88 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 69 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 78 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 16 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 19 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 13 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 10 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 8 | View all user solutions | Challenge discussion