• Challenges
  • Algorithms
  • Recently Added

    Largest FourNot Completed

    Solutions: 54 | View user solutions | Added 01/06/17

    Character RemovalNot Completed

    Solutions: 24 | View user solutions | Added 01/04/17

    Closest Enemy IINot Completed

    Solutions: 26 | View user solutions | Added 12/31/16

    You have access to 10 free challenges and solutions below

    Easy Difficulty

    First ReverseNot Completed

    Solutions: 62377 | Step-by-step solution | Challenge discussion

    First FactorialNot Completed

    Solutions: 43562 | Step-by-step solution | Challenge discussion

    Longest WordNot Completed

    Solutions: 35049 | Step-by-step solution | Challenge discussion

    Letter ChangesNot Completed

    Solutions: 33551 | Step-by-step solution | Challenge discussion

    Simple AddingNot Completed

    Solutions: 29073 | Step-by-step solution | Challenge discussion

    Letter CapitalizeNot Completed

    Solutions: 24800 | Step-by-step solution | Challenge discussion

    Simple SymbolsNot Completed

    Solutions: 18816 | Step-by-step solution | Challenge discussion

    Check NumsNot Completed

    Solutions: 20844 | Step-by-step solution | Challenge discussion

    Time ConvertNot Completed

    Solutions: 15619 | Step-by-step solution | Challenge discussion

    Alphabet SoupNot Completed

    Solutions: 14854 | Step-by-step solution | Challenge discussion

    AB CheckNot Completed

    Solutions: 13960 | Step-by-step solution | Challenge discussion

    Vowel CountNot Completed

    Solutions: 13451 | Step-by-step solution | Challenge discussion

    Word CountNot Completed

    Solutions: 12731 | Step-by-step solution | Challenge discussion

    Ex OhNot Completed

    Solutions: 12101 | Step-by-step solution | Challenge discussion

    PalindromeNot Completed

    Solutions: 14012 | Step-by-step solution | Challenge discussion

    Arith GeoNot Completed

    Solutions: 10813 | Step-by-step solution | Challenge discussion

    Array Addition INot Completed

    Solutions: 6751 | Step-by-step solution | Challenge discussion

    Letter Count INot Completed

    Solutions: 6101 | Step-by-step solution | Challenge discussion

    Second GreatLowNot Completed

    Solutions: 10494 | Step-by-step solution | Challenge discussion

    Division StringifiedNot Completed

    Solutions: 7915 | Step-by-step solution | Challenge discussion

    Counting Minutes INot Completed

    Solutions: 4706 | Step-by-step solution | Challenge discussion

    Mean ModeNot Completed

    Solutions: 6231 | Step-by-step solution | Challenge discussion

    Dash InsertNot Completed

    Solutions: 6889 | Step-by-step solution | Challenge discussion

    Swap CaseNot Completed

    Solutions: 6780 | Step-by-step solution | Challenge discussion

    Number AdditionNot Completed

    Solutions: 6601 | Step-by-step solution | Challenge discussion

    Third GreatestNot Completed

    Solutions: 6088 | Step-by-step solution | Challenge discussion

    Powers of TwoNot Completed

    Solutions: 6705 | Step-by-step solution | Challenge discussion

    Additive PersistenceNot Completed

    Solutions: 4630 | Step-by-step solution | Challenge discussion

    Multiplicative PersistenceNot Completed

    Solutions: 3657 | Step-by-step solution | Challenge discussion

    Off Line MinimumNot Completed

    Solutions: 4829 | Step-by-step solution | Challenge discussion

    Changing SequenceNot Completed

    Solutions: 1395 | Step-by-step solution | Challenge discussion

    Overlapping RangesNot Completed

    Solutions: 1406 | Step-by-step solution | Challenge discussion

    SuperincreasingNot Completed

    Solutions: 1370 | Step-by-step solution | Challenge discussion

    Hamming DistanceNot Completed

    Solutions: 928 | Step-by-step solution | Challenge discussion

    Rectangle AreaNot Completed

    Solutions: 1136 | Step-by-step solution | Challenge discussion

    Bitwise OneNot Completed

    Solutions: 951 | Step-by-step solution | Challenge discussion

    Other ProductsNot Completed

    Solutions: 605 | Step-by-step solution | Challenge discussion

    Wave SortingNot Completed

    Solutions: 445 | Step-by-step solution | Challenge discussion

    Array MatchingNot Completed

    Solutions: 490 | Step-by-step solution | Challenge discussion

    Binary ReversalNot Completed

    Solutions: 452 | Step-by-step solution | Challenge discussion

    Longest Increasing SequenceNot Completed

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

    Even PairsNot Completed

    Solutions: 367 | Step-by-step solution | Challenge discussion

    Next PalindromeNot Completed

    Solutions: 351 | Step-by-step solution | Challenge discussion

    Largest PairNot Completed

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

    Nonrepeating CharacterNot Completed

    Solutions: 349 | Step-by-step solution | Challenge discussion

    Two SumNot Completed

    Solutions: 587 | Step-by-step solution | Challenge discussion

    Bitwise TwoNot Completed

    Solutions: 227 | Step-by-step solution | Challenge discussion

    Power Set CountNot Completed

    Solutions: 314 | Step-by-step solution | Challenge discussion

    Product DigitsNot Completed

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

    Palindrome CreatorNot Completed

    Solutions: 336 | Step-by-step solution | Challenge discussion

    Basic Roman NumeralsNot Completed

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

    Food DistributionNot Completed

    Solutions: 168 | Step-by-step solution | Challenge discussion

    Three SumNot Completed

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

    Correct PathNot Completed

    Solutions: 115 | Step-by-step solution | Challenge discussion

    Scale BalancingNot Completed

    Solutions: 169 | Step-by-step solution | Challenge discussion

    Three NumbersNot Completed

    Solutions: 154 | Step-by-step solution | Challenge discussion

    Alphabet SearchingNot Completed

    Solutions: 147 | Step-by-step solution | Challenge discussion

    Time DifferenceNot Completed

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

    Triangle RowNot Completed

    Solutions: 84 | Step-by-step solution | Challenge discussion

    Vowel SquareNot Completed

    Solutions: 102 | Step-by-step solution | Challenge discussion

    Closest EnemyNot Completed

    Solutions: 65 | Step-by-step solution | Challenge discussion

    Closest Enemy IINot Completed

    Solutions: 26 | Step-by-step solution | Challenge discussion

    Largest FourNot Completed

    Solutions: 54 | Step-by-step solution | Challenge discussion

    Medium Difficulty

    Prime TimeNot Completed

    Solutions: 10561 | Step-by-step solution | Challenge discussion

    Run Length Not Completed

    Solutions: 7356 | Step-by-step solution | Challenge discussion

    Prime MoverNot Completed

    Solutions: 6638 | Step-by-step solution | Challenge discussion

    Palindrome TwoNot Completed

    Solutions: 6159 | Step-by-step solution | Challenge discussion

    DivisionNot Completed

    Solutions: 5568 | Step-by-step solution | Challenge discussion

    String ScrambleNot Completed

    Solutions: 6146 | Step-by-step solution | Challenge discussion

    Arith Geo IINot Completed

    Solutions: 4363 | Step-by-step solution | Challenge discussion

    Array AdditionNot Completed

    Solutions: 3586 | Step-by-step solution | Challenge discussion

    Binary ConverterNot Completed

    Solutions: 4074 | Step-by-step solution | Challenge discussion

    Letter CountNot Completed

    Solutions: 3719 | Step-by-step solution | Challenge discussion

    Simple ModeNot Completed

    Solutions: 4096 | Step-by-step solution | Challenge discussion

    Caesar CipherNot Completed

    Solutions: 4353 | Step-by-step solution | Challenge discussion

    Formatted DivisionNot Completed

    Solutions: 3197 | Step-by-step solution | Challenge discussion

    ConsecutiveNot Completed

    Solutions: 3533 | Step-by-step solution | Challenge discussion

    Counting MinutesNot Completed

    Solutions: 2377 | View all user solutions | Challenge discussion

    Permutation StepNot Completed

    Solutions: 2763 | View all user solutions | Challenge discussion

    Prime CheckerNot Completed

    Solutions: 2108 | View all user solutions | Challenge discussion

    Dash Insert IINot Completed

    Solutions: 4283 | View all user solutions | Challenge discussion

    Swap IINot Completed

    Solutions: 2329 | View all user solutions | Challenge discussion

    Number SearchNot Completed

    Solutions: 2815 | View all user solutions | Challenge discussion

    Triple DoubleNot Completed

    Solutions: 2615 | View all user solutions | Challenge discussion

    Bracket MatcherNot Completed

    Solutions: 2405 | View all user solutions | Challenge discussion

    String ReductionNot Completed

    Solutions: 2013 | View all user solutions | Challenge discussion

    Coin DeterminerNot Completed

    Solutions: 1948 | View all user solutions | Challenge discussion

    ThreeFive MultiplesNot Completed

    Solutions: 2449 | View all user solutions | Challenge discussion

    Fibonacci CheckerNot Completed

    Solutions: 2288 | View all user solutions | Challenge discussion

    Multiple BracketsNot Completed

    Solutions: 1936 | View all user solutions | Challenge discussion

    Most Free TimeNot Completed

    Solutions: 1222 | View all user solutions | Challenge discussion

    Overlapping RectanglesNot Completed

    Solutions: 1373 | View all user solutions | Challenge discussion

    Distinct ListNot Completed

    Solutions: 2085 | View all user solutions | Challenge discussion

    Look Say SequenceNot Completed

    Solutions: 1207 | View all user solutions | Challenge discussion

    Number EncodingNot Completed

    Solutions: 1246 | View all user solutions | Challenge discussion

    Stock PickerNot Completed

    Solutions: 450 | View all user solutions | Challenge discussion

    Max SubarrayNot Completed

    Solutions: 335 | View all user solutions | Challenge discussion

    Missing DigitNot Completed

    Solutions: 227 | View all user solutions | Challenge discussion

    K Unique CharactersNot Completed

    Solutions: 208 | View all user solutions | Challenge discussion

    Bitmap HolesNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Symmetric TreeNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Binary Search Tree LCANot Completed

    Solutions: 127 | View all user solutions | Challenge discussion

    Binary Tree LCANot Completed

    Solutions: 67 | View all user solutions | Challenge discussion

    LRU CacheNot Completed

    Solutions: 57 | View all user solutions | Challenge discussion

    Tree ConstructorNot Completed

    Solutions: 56 | View all user solutions | Challenge discussion

    Array Min JumpsNot Completed

    Solutions: 86 | View all user solutions | Challenge discussion

    Nearest Smaller ValuesNot Completed

    Solutions: 149 | View all user solutions | Challenge discussion

    Matrix SpiralNot Completed

    Solutions: 70 | View all user solutions | Challenge discussion

    Word SplitNot Completed

    Solutions: 133 | View all user solutions | Challenge discussion

    Pair SearchingNot Completed

    Solutions: 43 | View all user solutions | Challenge discussion

    Boggle SolverNot Completed

    Solutions: 29 | View all user solutions | Challenge discussion

    HTML ElementsNot Completed

    Solutions: 40 | View all user solutions | Challenge discussion

    Missing Digit IINot Completed

    Solutions: 52 | View all user solutions | Challenge discussion

    Palindromic SubstringNot Completed

    Solutions: 81 | View all user solutions | Challenge discussion

    Trapping WaterNot Completed

    Solutions: 59 | View all user solutions | Challenge discussion

    Matrix PathNot Completed

    Solutions: 37 | View all user solutions | Challenge discussion

    Seating StudentsNot Completed

    Solutions: 41 | View all user solutions | Challenge discussion

    Longest Matrix PathNot Completed

    Solutions: 20 | View all user solutions | Challenge discussion

    Min Window SubstringNot Completed

    Solutions: 38 | View all user solutions | Challenge discussion

    Matrix ChainsNot Completed

    Solutions: 23 | View all user solutions | Challenge discussion

    Histogram AreaNot Completed

    Solutions: 30 | View all user solutions | Challenge discussion

    Matching CharactersNot Completed

    Solutions: 33 | View all user solutions | Challenge discussion

    Ternary ConverterNot Completed

    Solutions: 20 | View all user solutions | Challenge discussion

    Linear CongruenceNot Completed

    Solutions: 11 | View all user solutions | Challenge discussion

    Formatted NumberNot Completed

    Solutions: 29 | View all user solutions | Challenge discussion

    Largest Row ColumnNot Completed

    Solutions: 10 | View all user solutions | Challenge discussion

    Eight QueensNot Completed

    Solutions: 16 | View all user solutions | Challenge discussion

    Three PointsNot Completed

    Solutions: 33 | View all user solutions | Challenge discussion

    Character RemovalNot Completed

    Solutions: 24 | View all user solutions | Challenge discussion

    Hard Difficulty

    Shortest PathNot Completed

    Solutions: 900 | View all user solutions | Challenge discussion

    Pattern ChaserNot Completed

    Solutions: 582 | View all user solutions | Challenge discussion

    CalculatorNot Completed

    Solutions: 1017 | View all user solutions | Challenge discussion

    Weighted PathNot Completed

    Solutions: 306 | View all user solutions | Challenge discussion

    Intersecting LinesNot Completed

    Solutions: 498 | View all user solutions | Challenge discussion

    RREF MatrixNot Completed

    Solutions: 103 | View all user solutions | Challenge discussion

    Polynomial ExpansionNot Completed

    Solutions: 261 | View all user solutions | Challenge discussion

    Gas StationNot Completed

    Solutions: 497 | View all user solutions | Challenge discussion

    Symmetric MatrixNot Completed

    Solutions: 345 | View all user solutions | Challenge discussion

    Switch SortNot Completed

    Solutions: 247 | View all user solutions | Challenge discussion

    Matrix DeterminantNot Completed

    Solutions: 236 | View all user solutions | Challenge discussion

    Queen CheckNot Completed

    Solutions: 403 | View all user solutions | Challenge discussion

    Noughts DeterminerNot Completed

    Solutions: 340 | View all user solutions | Challenge discussion

    Blackjack HighestNot Completed

    Solutions: 454 | View all user solutions | Challenge discussion

    Transitivity RelationsNot Completed

    Solutions: 396 | View all user solutions | Challenge discussion

    Alphabet Run EncryptionNot Completed

    Solutions: 220 | View all user solutions | Challenge discussion

    Knight JumpsNot Completed

    Solutions: 482 | View all user solutions | Challenge discussion

    Line OrderingNot Completed

    Solutions: 45 | View all user solutions | Challenge discussion

    Sudoku Quadrant CheckerNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Quick KnightNot Completed

    Solutions: 38 | View all user solutions | Challenge discussion

    Square FiguresNot Completed

    Solutions: 94 | View all user solutions | Challenge discussion

    Connect Four WinnerNot Completed

    Solutions: 62 | 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: 55 | View all user solutions | Challenge discussion

    Parallel SumsNot Completed

    Solutions: 77 | View all user solutions | Challenge discussion

    LCSNot Completed

    Solutions: 48 | View all user solutions | Challenge discussion

    Nim WinnerNot Completed

    Solutions: 34 | View all user solutions | Challenge discussion

    Farthest NodesNot Completed

    Solutions: 131 | View all user solutions | Challenge discussion

    Optimal AssignmentsNot Completed

    Solutions: 473 | View all user solutions | Challenge discussion

    Kaprekars ConstantNot Completed

    Solutions: 74 | View all user solutions | Challenge discussion

    Hamiltonian PathNot Completed

    Solutions: 123 | View all user solutions | Challenge discussion

    Vertex CoveringNot Completed

    Solutions: 126 | View all user solutions | Challenge discussion

    Step WalkingNot Completed

    Solutions: 63 | View all user solutions | Challenge discussion

    Pascals TriangleNot Completed

    Solutions: 66 | View all user solutions | Challenge discussion

    Reverse Polish NotationNot Completed

    Solutions: 179 | View all user solutions | Challenge discussion

    Max Heap CheckerNot Completed

    Solutions: 62 | View all user solutions | Challenge discussion

    Chessboard TravelingNot Completed

    Solutions: 41 | View all user solutions | Challenge discussion

    Matching CouplesNot Completed

    Solutions: 73 | View all user solutions | Challenge discussion

    Approaching FibonacciNot Completed

    Solutions: 87 | View all user solutions | Challenge discussion

    Simple SATNot Completed

    Solutions: 46 | View all user solutions | Challenge discussion

    Array CouplesNot Completed

    Solutions: 61 | View all user solutions | Challenge discussion

    Array RotationNot Completed

    Solutions: 100 | View all user solutions | Challenge discussion

    Bracket CombinationsNot Completed

    Solutions: 72 | View all user solutions | Challenge discussion

    Counting AnagramsNot Completed

    Solutions: 85 | View all user solutions | Challenge discussion

    Maximal SquareNot Completed

    Solutions: 20 | View all user solutions | Challenge discussion

    Maximal RectangleNot Completed

    Solutions: 22 | View all user solutions | Challenge discussion

    Bipartite MatchingNot Completed

    Solutions: 16 | View all user solutions | Challenge discussion

    Pentagonal NumberNot Completed

    Solutions: 15 | View all user solutions | Challenge discussion

    City TrafficNot Completed

    Solutions: 16 | View all user solutions | Challenge discussion

    Convex Hull PointsNot Completed

    Solutions: 10 | View all user solutions | Challenge discussion