Question Bank
Top 100
The most frequently asked interview problems at top tech companies. Curated and categorized.
100 problems16 Easy·63 Medium·21 Hard
Q001
Two SumArrays & Hashing
GoogleAmazonMeta
EasyQ002
Add Two NumbersLinked Lists
AmazonMicrosoft
MediumQ003
Longest Substring Without Repeating CharactersSliding Window
AmazonGoogleMeta
MediumQ004
Median of Two Sorted ArraysBinary Search
GoogleAmazon
HardQ005
Longest Palindromic SubstringStrings
AmazonMetaMicrosoft
MediumQ006
Reverse IntegerMath
AmazonBloomberg
MediumQ007
String to Integer (atoi)Strings
MicrosoftAmazon
MediumQ008
Palindrome NumberMath
Amazon
EasyQ009
Regular Expression MatchingDynamic Programming
GoogleAmazonMeta
HardQ010
Container With Most WaterTwo Pointers
AmazonGoogleMeta
MediumQ011
3SumTwo Pointers
AmazonGoogleMeta
MediumQ012
Letter Combinations of a Phone NumberBacktracking
AmazonGoogle
MediumQ013
Generate ParenthesesBacktracking
AmazonGoogleMeta
MediumQ014
Merge K Sorted ListsLinked Lists
AmazonGoogleMeta
HardQ015
Valid ParenthesesStack
AmazonMetaBloomberg
EasyQ016
Merge Two Sorted ListsLinked Lists
AmazonMicrosoft
EasyQ017
Best Time to Buy and Sell StockDynamic Programming
AmazonMeta
EasyQ018
Climbing StairsDynamic Programming
AmazonGoogle
EasyQ019
Maximum SubarrayDynamic Programming
AmazonGoogleMicrosoft
MediumQ020
Jump GameGreedy
AmazonGoogle
MediumQ021
Merge IntervalsIntervals
AmazonGoogleMeta
MediumQ022
Unique PathsDynamic Programming
AmazonGoogle
MediumQ023
Minimum Path SumDynamic Programming
AmazonGoogle
MediumQ024
Sort ColorsTwo Pointers
AmazonMicrosoft
MediumQ025
SubsetsBacktracking
AmazonGoogle
MediumQ026
Word SearchBacktracking
AmazonMicrosoft
MediumQ027
CandyGreedy
Amazon
HardQ028
Trapping Rain WaterTwo Pointers
AmazonGoogleMeta
HardQ029
Binary Tree Maximum Path SumTrees
GoogleMeta
HardQ030
Serialize and Deserialize Binary TreeTrees
AmazonGoogleMeta
HardQ031
Valid Binary Search TreeTrees
AmazonGoogleMeta
MediumQ032
Lowest Common Ancestor of a Binary TreeTrees
AmazonGoogleMeta
MediumQ033
Binary Tree Level Order TraversalTrees
AmazonGoogle
MediumQ034
Convert Sorted Array to Binary Search TreeTrees
Amazon
EasyQ035
Maximum Depth of Binary TreeTrees
AmazonGoogle
EasyQ036
Invert Binary TreeTrees
Google
EasyQ037
Same TreeTrees
Amazon
EasyQ038
Number of IslandsGraphs
AmazonGoogleMeta
MediumQ039
Clone GraphGraphs
AmazonMeta
MediumQ040
Course ScheduleGraphs
AmazonGoogleMeta
MediumQ041
Pacific Atlantic Water FlowGraphs
GoogleAmazon
MediumQ042
Word LadderGraphs
AmazonGoogleMeta
HardQ043
Implement Trie (Prefix Tree)Trie
AmazonGoogle
MediumQ044
Design Add and Search Words Data StructureTrie
AmazonMeta
MediumQ045
Word Search IITrie
AmazonGoogleMeta
HardQ046
Top K Frequent ElementsHeap
AmazonMetaGoogle
MediumQ047
Find Median from Data StreamHeap
AmazonGoogleMeta
HardQ048
Task SchedulerHeap
MetaAmazon
MediumQ049
LRU CacheDesign
AmazonGoogleMeta
MediumQ050
Min StackStack
AmazonMicrosoft
MediumQ051
Evaluate Reverse Polish NotationStack
Amazon
MediumQ052
Daily TemperaturesStack
AmazonGoogle
MediumQ053
Car FleetStack
Amazon
MediumQ054
Largest Rectangle in HistogramStack
AmazonGoogle
HardQ055
Sliding Window MaximumSliding Window
AmazonGoogleMeta
HardQ056
Minimum Window SubstringSliding Window
AmazonMetaMicrosoft
HardQ057
Longest Repeating Character ReplacementSliding Window
Google
MediumQ058
Permutation in StringSliding Window
Amazon
MediumQ059
Best Time to Buy and Sell Stock with CooldownDynamic Programming
Google
MediumQ060
Coin ChangeDynamic Programming
AmazonGoogle
MediumQ061
Longest Increasing SubsequenceDynamic Programming
AmazonGoogleMeta
MediumQ062
Word BreakDynamic Programming
AmazonGoogleMeta
MediumQ063
House RobberDynamic Programming
Amazon
MediumQ064
Unique Binary Search TreesDynamic Programming
Amazon
MediumQ065
Decode WaysDynamic Programming
AmazonGoogle
MediumQ066
Longest Common SubsequenceDynamic Programming
AmazonGoogle
MediumQ067
Edit DistanceDynamic Programming
AmazonGoogle
MediumQ068
Interleaving StringDynamic Programming
AmazonGoogle
HardQ069
Burst BalloonsDynamic Programming
Amazon
HardQ070
Longest Valid ParenthesesDynamic Programming
AmazonGoogle
HardQ071
Median of a Sorted MatrixBinary Search
Google
HardQ072
Koko Eating BananasBinary Search
Google
MediumQ073
Search in Rotated Sorted ArrayBinary Search
AmazonGoogle
MediumQ074
Find Minimum in Rotated Sorted ArrayBinary Search
AmazonGoogle
MediumQ075
Time Based Key-Value StoreBinary Search
Google
MediumQ076
Design TwitterDesign
Amazon
MediumQ077
Design Underground SystemDesign
Meta
MediumQ078
Snapshot ArrayDesign
Meta
MediumQ079
All O'one Data StructureDesign
Amazon
HardQ080
LRU Cache Doubly Linked ListLinked Lists
AmazonMicrosoft
MediumQ081
Reverse Nodes in k-GroupLinked Lists
AmazonMeta
HardQ082
Swap Nodes in PairsLinked Lists
Amazon
MediumQ083
Rotate ListLinked Lists
Amazon
MediumQ084
Remove Nth Node From End of ListLinked Lists
AmazonGoogle
MediumQ085
Reorder ListLinked Lists
AmazonMeta
MediumQ086
Palindrome Linked ListLinked Lists
AmazonMeta
EasyQ087
Missing NumberMath
AmazonMicrosoft
EasyQ088
Counting BitsBit Manipulation
Amazon
EasyQ089
Sum of Two IntegersBit Manipulation
Amazon
MediumQ090
Reverse BitsBit Manipulation
Amazon
EasyQ091
Single NumberBit Manipulation
AmazonGoogle
EasyQ092
Number of 1 BitsBit Manipulation
Amazon
EasyQ093
Alien DictionaryGraphs
AmazonGoogleMeta
HardQ094
Graph Valid TreeGraphs
AmazonGoogle
MediumQ095
Number of Connected ComponentsGraphs
AmazonGoogle
MediumQ096
Rotting OrangesGraphs
AmazonGoogle
MediumQ097
Redundant ConnectionGraphs
Amazon
MediumQ098
Accounts MergeGraphs
AmazonGoogle
MediumQ099
Is Graph BipartiteGraphs
AmazonGoogle
MediumQ100
Longest Increasing Path in a MatrixGraphs
AmazonGoogleMeta
Hard