1Serialize and Deserialize N-ary TreeHardStringTreeDepth-First Search
Solve → 2Decode StringMediumStringStackRecursion
Solve → 3Decode StringMediumStringStackRecursion
Solve → 4Serialize and Deserialize Binary TreeHardStringTreeDepth-First Search
Solve → 5Longest Valid ParenthesesHardStringDynamic ProgrammingStack
Solve → 6Serialize and Deserialize N-ary TreeHardStringTreeDepth-First Search
Solve → 7Decode StringMediumStringStackRecursion
Solve → 8Longest Happy StringMediumStringGreedyHeap (Priority Queue)
Solve → 9Valid ParenthesesEasyStringStack
Solve → 10Generate ParenthesesMediumStringDynamic ProgrammingBacktracking
Solve → 11Valid Parenthesis StringMediumStringDynamic ProgrammingStack
Solve → 12Minimum Cost Good CaptionHardStringDynamic Programming
Solve → 13Lexicographically Smallest Generated StringHardStringGreedyString Matching
Solve → 14Simplify PathMediumStringStack
Solve → 15Edit DistanceMediumStringDynamic Programming
Solve → 16Serialize and Deserialize Binary TreeHardStringTreeDepth-First Search
Solve → 17Design Add and Search Words Data StructureMediumStringDepth-First SearchDesign
Solve → 18Regular Expression MatchingHardStringDynamic ProgrammingRecursion
Solve → 19Remove Duplicate LettersMediumStringStackGreedy
Solve → 20Restore IP AddressesMediumStringBacktracking
Solve → 21Minimum Remove to Make Valid ParenthesesMediumStringStack
Solve → 22Split Message Based on LimitHardStringEnumeration
Solve → 23Score of ParenthesesMediumStringStack
Solve → 24Remove All Adjacent Duplicates in String IIMediumStringStack
Solve → 25Longest Valid ParenthesesHardStringDynamic ProgrammingStack
Solve → 26Remove Invalid ParenthesesHardStringBacktrackingBreadth-First Search
Solve → 27Design Search Autocomplete SystemHardStringDepth-First SearchDesign
Solve → 28Step-By-Step Directions From a Binary Tree Node to AnotherMediumStringTreeDepth-First Search
Solve → 29Remove K DigitsMediumStringStackGreedy
Solve → 30Longest Common SubsequenceMediumStringDynamic Programming
Solve → 31Letter Case PermutationMediumStringBacktrackingBit Manipulation
Solve → 32Longest Duplicate SubstringHardStringBinary SearchSliding Window
Solve → 33Decode WaysMediumStringDynamic Programming
Solve → 34Validate IP AddressMediumString
Solve → 35Length of the Longest Alphabetical Continuous SubstringMediumString
Solve → 36Valid Palindrome IIIHardStringDynamic Programming
Solve → 37Construct String from Binary TreeMediumStringTreeDepth-First Search
Solve → 38Decode StringMediumStringStackRecursion
Solve → 39Valid ParenthesesEasyStringStack
Solve → 40Longest Happy StringMediumStringGreedyHeap (Priority Queue)
Solve → 41Generate ParenthesesMediumStringDynamic ProgrammingBacktracking
Solve → 42Valid Parenthesis StringMediumStringDynamic ProgrammingStack
Solve → 43Edit DistanceMediumStringDynamic Programming
Solve → 44Serialize and Deserialize Binary TreeHardStringTreeDepth-First Search
Solve → 45Length of the Longest Alphabetical Continuous SubstringMediumString
Solve → 46Minimum Cost Good CaptionHardStringDynamic Programming
Solve → 47Lexicographically Smallest Generated StringHardStringGreedyString Matching
Solve → 48Simplify PathMediumStringStack
Solve → 49Design Add and Search Words Data StructureMediumStringDepth-First SearchDesign
Solve → 50Regular Expression MatchingHardStringDynamic ProgrammingRecursion
Solve → 51Restore IP AddressesMediumStringBacktracking
Solve → 52Remove Duplicate LettersMediumStringStackGreedy
Solve → 53Minimum Remove to Make Valid ParenthesesMediumStringStack
Solve → 54Longest Valid ParenthesesHardStringDynamic ProgrammingStack
Solve → 55Remove Invalid ParenthesesHardStringBacktrackingBreadth-First Search
Solve → 56Split Message Based on LimitHardStringEnumeration
Solve → 57Score of ParenthesesMediumStringStack
Solve → 58Remove All Adjacent Duplicates in String IIMediumStringStack
Solve → 59Remove K DigitsMediumStringStackGreedy
Solve → 60Design Search Autocomplete SystemHardStringDepth-First SearchDesign
Solve → 61Longest Common SubsequenceMediumStringDynamic Programming
Solve → 62Step-By-Step Directions From a Binary Tree Node to AnotherMediumStringTreeDepth-First Search
Solve → 63Letter Case PermutationMediumStringBacktrackingBit Manipulation
Solve → 64Longest Duplicate SubstringHardStringBinary SearchSliding Window
Solve → 65Serialize and Deserialize N-ary TreeHardStringTreeDepth-First Search
Solve → 66Decode WaysMediumStringDynamic Programming
Solve → 67Validate IP AddressMediumString
Solve → 68Valid Palindrome IIIHardStringDynamic Programming
Solve → 69Construct String from Binary TreeMediumStringTreeDepth-First Search
Solve →