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HackWithInfy Prep • 226 items

1Accounts MergeMedium
ArrayHash TableString
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2Add Edges to Make Degrees of All Nodes EvenHard
Hash TableGraph Theory
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3Alien DictionaryHard
ArrayStringDepth-First Search
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4All Ancestors of a Node in a Directed Acyclic GraphMedium
Depth-First SearchBreadth-First SearchGraph Theory
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5All Paths from Source Lead to DestinationMedium
Graph TheoryTopological Sort
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6All Paths From Source to TargetMedium
BacktrackingDepth-First SearchBreadth-First Search
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7Apply SubstitutionsMedium
ArrayHash TableString
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8Array NestingMedium
ArrayDepth-First Search
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9Battleships in a BoardMedium
ArrayDepth-First SearchMatrix
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10Brace Expansion IIHard
Hash TableStringBacktracking
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11Brace ExpansionMedium
StringBacktrackingStack
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12Build a Matrix With ConditionsHard
ArrayGraph TheoryTopological Sort
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13Bulb Switcher IIMedium
MathBit ManipulationDepth-First Search
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14Bus RoutesHard
ArrayHash TableBreadth-First Search
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15Check for Contradictions in EquationsHard
ArrayDepth-First SearchUnion-Find
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16Check if the Rectangle Corner Is ReachableHard
ArrayMathDepth-First Search
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17Check if There is a Valid Path in a GridMedium
ArrayDepth-First SearchBreadth-First Search
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18Check Knight Tour ConfigurationMedium
ArrayDepth-First SearchBreadth-First Search
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19Checking Existence of Edge Length Limited PathsHard
ArrayTwo PointersUnion-Find
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20Clone GraphMedium
Hash TableDepth-First SearchBreadth-First Search
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21Coloring A BorderMedium
ArrayDepth-First SearchBreadth-First Search
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22Contain VirusHard
ArrayDepth-First SearchBreadth-First Search
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23Count Islands With Total Value Divisible by KMedium
ArrayDepth-First SearchBreadth-First Search
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24Count Pairs Of NodesHard
ArrayHash TableTwo Pointers
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25Count Servers that CommunicateMedium
ArrayDepth-First SearchBreadth-First Search
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26Count Sub IslandsMedium
ArrayDepth-First SearchBreadth-First Search
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27Count the Number of Complete ComponentsMedium
Depth-First SearchBreadth-First SearchUnion-Find
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28Count the Number of Houses at a Certain Distance IMedium
Breadth-First SearchGraph TheoryPrefix Sum
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29Count the Number of Houses at a Certain Distance IIHard
Graph TheoryPrefix Sum
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30Count Unreachable Pairs of Nodes in an Undirected GraphMedium
Depth-First SearchBreadth-First SearchUnion-Find
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31Couples Holding HandsHard
GreedyDepth-First SearchBreadth-First Search
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32Course Schedule IIMedium
Depth-First SearchBreadth-First SearchGraph Theory
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33Course Schedule IVMedium
Depth-First SearchBreadth-First SearchGraph Theory
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34Course ScheduleMedium
Depth-First SearchBreadth-First SearchGraph Theory
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35Cracking the SafeHard
StringDepth-First SearchGraph Theory
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36Critical Connections in a NetworkHard
Depth-First SearchGraph TheoryBiconnected Component
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37Cut Off Trees for Golf EventHard
ArrayBreadth-First SearchHeap (Priority Queue)
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38Design Add and Search Words Data StructureMedium
StringDepth-First SearchDesign
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39Design Excel Sum FormulaHard
ArrayHash TableString
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40Design Graph With Shortest Path CalculatorHard
Graph TheoryDesignHeap (Priority Queue)
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41Design Search Autocomplete SystemHard
StringDepth-First SearchDesign
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42Detect Cycles in 2D GridMedium
ArrayDepth-First SearchBreadth-First Search
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43Detonate the Maximum BombsMedium
ArrayMathDepth-First Search
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44Digit Operations to Make Two Integers EqualMedium
MathGraph TheoryHeap (Priority Queue)
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45Distance to a Cycle in Undirected GraphHard
Depth-First SearchBreadth-First SearchGraph Theory
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46Divide Nodes Into the Maximum Number of GroupsHard
Depth-First SearchBreadth-First SearchUnion-Find
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47Escape a Large MazeHard
ArrayHash TableDepth-First Search
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48Escape the Spreading FireHard
ArrayBinary SearchBreadth-First Search
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49Evaluate DivisionMedium
ArrayStringDepth-First Search
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50Find a Safe Walk Through a GridMedium
ArrayBreadth-First SearchGraph Theory
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51Find All Groups of FarmlandMedium
ArrayDepth-First SearchBreadth-First Search
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52Find All People With SecretHard
Depth-First SearchBreadth-First SearchUnion-Find
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53Find All Possible Recipes from Given SuppliesMedium
ArrayHash TableString
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54Find Center of Star GraphEasy
Graph Theory
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55Find Champion IIMedium
Graph Theory
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56Find Closest Node to Given Two NodesMedium
Depth-First SearchGraph Theory
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57Find Edges in Shortest PathsHard
Depth-First SearchBreadth-First SearchGraph Theory
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58Find Eventual Safe StatesMedium
Depth-First SearchBreadth-First SearchGraph Theory
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59Find if Path Exists in GraphEasy
Depth-First SearchBreadth-First SearchUnion-Find
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60Find Minimum Time to Reach Last Room IMedium
ArrayGraph TheoryHeap (Priority Queue)
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61Find Minimum Time to Reach Last Room IIMedium
ArrayGraph TheoryHeap (Priority Queue)
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62Find Shortest Path with K HopsHard
Graph TheoryHeap (Priority Queue)Shortest Path
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63Find the CelebrityMedium
Two PointersGraph TheoryInteractive
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64Find the Safest Path in a GridMedium
ArrayBinary SearchBreadth-First Search
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65Find the Town JudgeEasy
ArrayHash TableGraph Theory
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66Flatten a Multilevel Doubly Linked ListMedium
Linked ListDepth-First SearchDoubly-Linked List
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67Flood FillEasy
ArrayDepth-First SearchBreadth-First Search
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68Flower Planting With No AdjacentMedium
Depth-First SearchBreadth-First SearchGraph Theory
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69Frequencies of Shortest SupersequencesHard
ArrayStringBit Manipulation
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70Get Watched Videos by Your FriendsMedium
ArrayHash TableBreadth-First Search
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71Graph Valid TreeMedium
Depth-First SearchBreadth-First SearchUnion-Find
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72Grid Teleportation TraversalMedium
ArrayHash TableBreadth-First Search
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73Implement Magic DictionaryMedium
Hash TableStringDepth-First Search
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74Is Graph Bipartite?Medium
Depth-First SearchBreadth-First SearchUnion-Find
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75Island PerimeterEasy
ArrayDepth-First SearchBreadth-First Search
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76Jump Game IIIMedium
ArrayDepth-First SearchBreadth-First Search
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77Jump Game IVHard
ArrayHash TableBreadth-First Search
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78K Highest Ranked Items Within a Price RangeMedium
ArrayBreadth-First SearchSorting
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79K-Similar StringsHard
Hash TableStringBreadth-First Search
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80Keys and RoomsMedium
Depth-First SearchBreadth-First SearchGraph Theory
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81Last Day Where You Can Still CrossHard
ArrayBinary SearchDepth-First Search
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82Lexicographical NumbersMedium
Depth-First SearchTrie
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83Lexicographically Smallest String After Applying OperationsMedium
StringDepth-First SearchBreadth-First Search
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84Longest Absolute File PathMedium
StringStackDepth-First Search
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85Longest Cycle in a GraphHard
Depth-First SearchBreadth-First SearchGraph Theory
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86Longest Word With All PrefixesMedium
ArrayStringDepth-First Search
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87Loud and RichMedium
ArrayDepth-First SearchGraph Theory
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88Making A Large IslandHard
ArrayDepth-First SearchBreadth-First Search
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89Map of Highest PeakMedium
ArrayBreadth-First SearchMatrix
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90Max Area of IslandMedium
ArrayDepth-First SearchBreadth-First Search
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91Maximal Network RankMedium
Graph Theory
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92Maximize Amount After Two Days of ConversionsMedium
ArrayStringDepth-First Search
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93Maximum Candies You Can Get from BoxesHard
ArrayBreadth-First SearchGraph Theory
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94Maximum Genetic Difference QueryHard
ArrayHash TableBit Manipulation
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95Maximum Number of Accepted InvitationsMedium
ArrayDepth-First SearchGraph Theory
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96Maximum Number of Fish in a GridMedium
ArrayDepth-First SearchBreadth-First Search
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97Maximum Number of Moves to Kill All PawnsHard
ArrayMathBit Manipulation
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98Maximum Number of Points From Grid QueriesHard
ArrayTwo PointersBreadth-First Search
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99Maximum Partition FactorHard
ArrayBinary SearchDepth-First Search
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100Maximum Path Quality of a GraphHard
ArrayBacktrackingGraph Theory
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101Maximum Score of a Node SequenceHard
ArrayGraph TheorySorting
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102Maximum Star Sum of a GraphMedium
ArrayGreedyGraph Theory
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103Maximum Sum of Edge Values in a GraphHard
MathGreedyGraph Theory
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104Maximum Total Importance of RoadsMedium
GreedyGraph TheorySorting
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105MinesweeperMedium
ArrayDepth-First SearchBreadth-First Search
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106Mini ParserMedium
StringStackDepth-First Search
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107Minimize Hamming Distance After Swap OperationsMedium
ArrayDepth-First SearchUnion-Find
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108Minimize Malware Spread IIHard
ArrayHash TableDepth-First Search
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109Minimize Malware SpreadHard
ArrayHash TableDepth-First Search
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110Minimize Maximum Component CostMedium
Binary SearchUnion-FindGraph Theory
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111Minimize Maximum Value in a GridHard
ArrayUnion-FindGraph Theory
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112Minimize the Maximum Edge Weight of GraphMedium
Binary SearchDepth-First SearchBreadth-First Search
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113Minimum Cost of a Path With Special RoadsMedium
ArrayGraph TheoryHeap (Priority Queue)
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114Minimum Cost Path with Edge ReversalsMedium
Graph TheoryHeap (Priority Queue)Shortest Path
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115Minimum Cost to Buy ApplesMedium
ArrayGraph TheoryHeap (Priority Queue)
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116Minimum Cost to Convert String IMedium
ArrayStringGraph Theory
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117Minimum Cost to Make at Least One Valid Path in a GridHard
ArrayBreadth-First SearchGraph Theory
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118Minimum Cost to Reach City With DiscountsMedium
Graph TheoryHeap (Priority Queue)Shortest Path
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119Minimum Cost Walk in Weighted GraphHard
ArrayBit ManipulationUnion-Find
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120Minimum Degree of a Connected Trio in a GraphHard
Graph TheoryEnumeration
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121Minimum Genetic MutationMedium
Hash TableStringBreadth-First Search
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122Minimum Height TreesMedium
Depth-First SearchBreadth-First SearchGraph Theory
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123Minimum Jumps to Reach End via Prime TeleportationMedium
ArrayHash TableMath
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124Minimum Jumps to Reach HomeMedium
ArrayHash TableBreadth-First Search
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125Minimum Knight MovesMedium
Breadth-First Search
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126Minimum Moves to Clean the ClassroomMedium
ArrayHash TableBit Manipulation
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127Minimum Moves to Move a Box to Their Target LocationHard
ArrayBreadth-First SearchHeap (Priority Queue)
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128Minimum Moves to Reach Target with RotationsHard
ArrayBreadth-First SearchMatrix
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129Minimum Number of Days to Disconnect IslandHard
ArrayDepth-First SearchBreadth-First Search
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130Minimum Number of Flips to Convert Binary Matrix to Zero MatrixHard
ArrayHash TableBit Manipulation
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131Minimum Number of Vertices to Reach All NodesMedium
Graph Theory
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132Minimum Obstacle Removal to Reach CornerHard
ArrayBreadth-First SearchGraph Theory
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133Minimum Operations to Convert NumberMedium
ArrayBreadth-First Search
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134Minimum Operations to Equalize Binary StringHard
MathStringBreadth-First Search
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135Minimum Operations to Remove Adjacent Ones in MatrixHard
ArrayGraph TheoryMatrix
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136Minimum Path Cost in a Hidden GridMedium
ArrayDepth-First SearchBreadth-First Search
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137Minimum Reverse OperationsHard
ArrayHash TableBreadth-First Search
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138Minimum Runes to Add to Cast SpellHard
ArrayDepth-First SearchBreadth-First Search
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139Minimum Score of a Path Between Two CitiesMedium
Depth-First SearchBreadth-First SearchUnion-Find
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140Minimum Time for K Connected ComponentsMedium
Binary SearchUnion-FindGraph Theory
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141Minimum Time Takes to Reach Destination Without DrowningHard
ArrayBreadth-First SearchMatrix
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142Minimum Time to Break Locks IIHard
ArrayDepth-First SearchGraph Theory
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143Minimum Time to Visit a Cell In a GridHard
ArrayBreadth-First SearchGraph Theory
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144Minimum Weighted Subgraph With the Required PathsHard
Graph TheoryHeap (Priority Queue)Shortest Path
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145Modify Graph Edge WeightsHard
Graph TheoryHeap (Priority Queue)Shortest Path
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146Most Stones Removed with Same Row or ColumnMedium
Hash TableDepth-First SearchUnion-Find
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147Nearest Exit from Entrance in MazeMedium
ArrayBreadth-First SearchMatrix
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148Nested List Weight Sum IIMedium
StackDepth-First SearchBreadth-First Search
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149Nested List Weight SumMedium
Depth-First SearchBreadth-First Search
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150Network Delay TimeMedium
Depth-First SearchBreadth-First SearchGraph Theory
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151Node With Highest Edge ScoreMedium
Hash TableGraph Theory
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152Number of Closed IslandsMedium
ArrayDepth-First SearchBreadth-First Search
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153Number of Connected Components in an Undirected GraphMedium
Depth-First SearchBreadth-First SearchUnion-Find
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154Number of Distinct Islands IIHard
ArrayHash TableDepth-First Search
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155Number of Distinct IslandsMedium
ArrayHash TableDepth-First Search
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156Number of EnclavesMedium
ArrayDepth-First SearchBreadth-First Search
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157Number of IslandsMedium
ArrayDepth-First SearchBreadth-First Search
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158Number of Operations to Make Network ConnectedMedium
Depth-First SearchBreadth-First SearchUnion-Find
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159Number of Possible Sets of Closing BranchesHard
Bit ManipulationGraph TheoryHeap (Priority Queue)
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160Number of ProvincesMedium
Depth-First SearchBreadth-First SearchUnion-Find
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161Numbers With Same Consecutive DifferencesMedium
BacktrackingBreadth-First Search
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162Open the LockMedium
ArrayHash TableString
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163Pacific Atlantic Water FlowMedium
ArrayDepth-First SearchBreadth-First Search
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164Parallel CoursesMedium
Graph TheoryTopological Sort
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165Path Existence Queries in a Graph IMedium
ArrayHash TableBinary Search
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166Path With Maximum Minimum ValueMedium
ArrayBinary SearchDepth-First Search
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167Path with Maximum ProbabilityMedium
ArrayGraph TheoryHeap (Priority Queue)
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168Path With Minimum EffortMedium
ArrayBinary SearchDepth-First Search
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169Paths in Maze That Lead to Same RoomMedium
Graph Theory
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170Possible BipartitionMedium
Depth-First SearchBreadth-First SearchUnion-Find
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171Power Grid MaintenanceMedium
ArrayHash TableDepth-First Search
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172Process Restricted Friend RequestsHard
Union-FindGraph Theory
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173Rank Transform of a MatrixHard
ArrayUnion-FindGraph Theory
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174Reachable Nodes In Subdivided GraphHard
Graph TheoryHeap (Priority Queue)Shortest Path
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175Reconstruct ItineraryHard
ArrayStringDepth-First Search
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176Redundant Connection IIHard
Depth-First SearchBreadth-First SearchUnion-Find
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177Redundant ConnectionMedium
Depth-First SearchBreadth-First SearchUnion-Find
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178Regions Cut By SlashesMedium
ArrayHash TableDepth-First Search
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179Remove All Ones With Row and Column Flips IIMedium
ArrayBit ManipulationBreadth-First Search
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180Remove Invalid ParenthesesHard
StringBacktrackingBreadth-First Search
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181Remove Max Number of Edges to Keep Graph Fully TraversableHard
Union-FindGraph Theory
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182Remove Methods From ProjectMedium
Depth-First SearchBreadth-First SearchGraph Theory
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183Remove Sub-Folders from the FilesystemMedium
ArrayStringDepth-First Search
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184Reorder Routes to Make All Paths Lead to the City ZeroMedium
Depth-First SearchBreadth-First SearchGraph Theory
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185Restore the Array From Adjacent PairsMedium
ArrayHash TableDepth-First Search
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186Rotting OrangesMedium
ArrayBreadth-First SearchMatrix
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187Satisfiability of Equality EquationsMedium
ArrayStringUnion-Find
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188Second Minimum Time to Reach DestinationHard
Breadth-First SearchGraph TheoryShortest Path
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189Sentence Similarity IIMedium
ArrayHash TableString
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190Sequence ReconstructionMedium
ArrayGraph TheoryTopological Sort
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191Shortest BridgeMedium
ArrayDepth-First SearchBreadth-First Search
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192Shortest Cycle in a GraphHard
Breadth-First SearchGraph Theory
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193Shortest Distance After Road Addition Queries IMedium
ArrayBreadth-First SearchGraph Theory
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194Shortest Distance from All BuildingsHard
ArrayBreadth-First SearchMatrix
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195Shortest Path in a Grid with Obstacles EliminationHard
ArrayBreadth-First SearchMatrix
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196Shortest Path in a Hidden GridMedium
ArrayDepth-First SearchBreadth-First Search
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197Shortest Path in Binary MatrixMedium
ArrayBreadth-First SearchMatrix
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198Shortest Path to Get All KeysHard
ArrayBit ManipulationBreadth-First Search
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199Shortest Path to Get FoodMedium
ArrayBreadth-First SearchMatrix
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200Shortest Path with Alternating ColorsMedium
Breadth-First SearchGraph Theory
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201Similar String GroupsHard
ArrayHash TableString
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202Smallest Rectangle Enclosing Black PixelsHard
ArrayBinary SearchDepth-First Search
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203Smallest String With SwapsMedium
ArrayHash TableString
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204Snakes and LaddersMedium
ArrayBreadth-First SearchMatrix
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205Sort Items by Groups Respecting DependenciesHard
Depth-First SearchBreadth-First SearchGraph Theory
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206Split and Merge Array TransformationMedium
ArrayHash TableBreadth-First Search
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207Stepping NumbersMedium
MathBacktrackingBreadth-First Search
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208Strange Printer IIHard
ArrayGraph TheoryTopological Sort
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209String Transforms Into Another StringHard
Hash TableStringGraph Theory
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210Sum of Remoteness of All CellsMedium
ArrayHash TableDepth-First Search
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211Surrounded RegionsMedium
ArrayDepth-First SearchBreadth-First Search
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212Swim in Rising WaterHard
ArrayBinary SearchDepth-First Search
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213The Maze IIMedium
ArrayDepth-First SearchBreadth-First Search
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214The Maze IIIHard
ArrayStringDepth-First Search
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215The MazeMedium
ArrayDepth-First SearchBreadth-First Search
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216The Time When the Network Becomes IdleMedium
ArrayBreadth-First SearchGraph Theory
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217Trapping Rain Water IIHard
ArrayBreadth-First SearchHeap (Priority Queue)
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218Unit Conversion IMedium
Depth-First SearchBreadth-First SearchGraph Theory
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219Valid Arrangement of PairsHard
ArrayDepth-First SearchGraph Theory
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220Walls and GatesMedium
ArrayBreadth-First SearchMatrix
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221Water and Jug ProblemMedium
MathDepth-First SearchBreadth-First Search
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222Web Crawler MultithreadedMedium
Depth-First SearchBreadth-First SearchConcurrency
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223Web CrawlerMedium
StringDepth-First SearchBreadth-First Search
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224Word Ladder IIHard
Hash TableStringBacktracking
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225Word LadderHard
Hash TableStringBreadth-First Search
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226Word SearchMedium
ArrayStringBacktracking
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227Maximum Good Subtree ScoreHard
ArrayDynamic ProgrammingBit Manipulation
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228Coin ChangeMedium
ArrayDynamic ProgrammingBreadth-First Search
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229Maximum Depth of Binary TreeEasy
TreeDepth-First SearchBreadth-First Search
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230Number of Nodes With Value OneMedium
TreeDepth-First SearchBreadth-First Search
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