Most Frequent Interview Questions

Math Graph Heap (Priority Queue)Number Theory Shortest Path

Rank

#1371MediumFrequency: 100%High Priority

Minimum Remove to Make Valid Parentheses

Rank

#1352HardFrequency: 100%High Priority

Maximum Profit in Job Scheduling

Array Binary Search Dynamic Programming Sorting

Rank

#232EasyFrequency: 100%High Priority

Implement Queue using Stacks

Stack Design Queue

Rank

#3613MediumFrequency: 100%High Priority

Maximize Amount After Two Days of Conversions

Array String Depth-First Search Breadth-First Search Graph

Rank

#716HardFrequency: 100%High Priority

Max Stack

Linked List Stack Design Doubly-Linked List Ordered Set

Rank

#1085MediumFrequency: 100%High Priority

The Earliest Moment When Everyone Become Friends

Array Union Find Sorting

Rank

#392EasyFrequency: 100%High Priority

Is Subsequence

Two Pointers String Dynamic Programming

#10

Rank

#64MediumFrequency: 100%High Priority

Minimum Path Sum

Array Dynamic Programming Matrix

#11

Rank

#817EasyFrequency: 100%High Priority

Design HashMap

Asked at DoorDash

Array Hash Table Linked List Design Hash Function

#12

Rank

#322MediumFrequency: 100%High Priority

Coin Change

Array Dynamic Programming Breadth-First Search

#13

Rank

#2383EasyFrequency: 100%High Priority

Add Two Integers

#14

Rank

#42HardFrequency: 100%High Priority

Trapping Rain Water

Array Two Pointers Dynamic Programming Stack Monotonic Stack

#15

Rank

#3681MediumFrequency: 100%High Priority

Maximum Area Rectangle With Point Constraints I

Array Math Binary Indexed Tree Segment Tree Geometry+2 more

#16

Rank

#1056MediumFrequency: 100%High Priority

Capacity To Ship Packages Within D Days

Array Binary Search

#17

Rank

#694MediumFrequency: 98%High Priority

Number of Distinct Islands

Hash Table Depth-First Search Breadth-First Search Union Find Hash Function

#18

Rank

#314MediumFrequency: 97%High Priority

Binary Tree Vertical Order Traversal

Hash Table Tree Depth-First Search Breadth-First Search Sorting+1 more

#19

Rank

#227MediumFrequency: 96%High Priority

Basic Calculator II

Math String Stack

#20

Rank

#680EasyFrequency: 95%High Priority

Valid Palindrome II

Two Pointers String Greedy

#21

Rank

#833HardFrequency: 95%High Priority

Bus Routes

Array Hash Table Breadth-First Search

#22

Rank

#739MediumFrequency: 94%High Priority

Daily Temperatures

#23

Rank

#415EasyFrequency: 94%High Priority

Add Strings

Math String Simulation

#24

Rank

#957MediumFrequency: 94%High Priority

Minimum Add to Make Parentheses Valid

String Stack Greedy

#25

Rank

#2891MediumFrequency: 93%High Priority

Maximum Beauty of an Array After Applying Operation

Array Binary Search Sliding Window Sorting

#26

Rank

#152MediumFrequency: 93%High Priority

Maximum Product Subarray

#27

Rank

#2MediumFrequency: 93%High Priority

Add Two Numbers

Linked List Math Recursion

#28

Rank

#84HardFrequency: 93%High Priority

Largest Rectangle in Histogram

#29

Rank

#234EasyFrequency: 93%High Priority

Palindrome Linked List

Linked List Two Pointers Stack Recursion

#30

Rank

#3639MediumFrequency: 93%High Priority

Zero Array Transformation I

Array Prefix Sum

#31

Rank

#88EasyFrequency: 92%High Priority

Merge Sorted Array

Array Two Pointers Sorting

#32

Rank

#215MediumFrequency: 92%High Priority

Kth Largest Element in an Array

Array Divide and Conquer Sorting Heap (Priority Queue)Quickselect

#33

Rank

#19MediumFrequency: 92%High Priority

Remove Nth Node From End of List

Linked List Two Pointers

#34

Rank

#1790MediumFrequency: 91%High Priority

Lowest Common Ancestor of a Binary Tree III

Hash Table Two Pointers Tree Binary Tree

#35

Rank

#129MediumFrequency: 91%High Priority

Sum Root to Leaf Numbers

Tree Depth-First Search Binary Tree

#36

Rank

#1046MediumFrequency: 91%High Priority

Max Consecutive Ones III

Array Binary Search Sliding Window Prefix Sum

#37

Rank

#65HardFrequency: 91%High Priority

Valid Number

#38

Rank

#1423MediumFrequency: 91%High Priority

Maximum Number of Occurrences of a Substring

Hash Table String Sliding Window

#39

Rank

#122MediumFrequency: 90%High Priority

Best Time to Buy and Sell Stock II

Array Dynamic Programming Greedy

#40

Rank

#20EasyFrequency: 90%High Priority

Valid Parentheses

#41

Rank

#121EasyFrequency: 89%High Priority

Best Time to Buy and Sell Stock

#42

Rank

#136EasyFrequency: 89%High Priority

Single Number

Array Bit Manipulation

#43

Rank

#852MediumFrequency: 89%High Priority

Friends Of Appropriate Ages

Array Two Pointers Binary Search Sorting

#44

Rank

#146MediumFrequency: 88%High Priority

LRU Cache

Hash Table Linked List Design Doubly-Linked List

#45

Rank

#364MediumFrequency: 88%High Priority

Nested List Weight Sum II

Stack Depth-First Search Breadth-First Search

#46

Rank

#7MediumFrequency: 88%High Priority

Reverse Integer

#47

Rank

#6MediumFrequency: 88%High Priority

Zigzag Conversion

#48

Rank

#408EasyFrequency: 87%High Priority

Valid Word Abbreviation

Two Pointers String

#49

Rank

#912MediumFrequency: 87%High Priority

Random Pick with Weight

Array Math Binary Search Prefix Sum Randomized

#50

Rank

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Most Frequent Interview Questions

The top 50 most frequently asked coding interview questions across all major tech companies.

Total Problems

Easy

Medium

Hard

95%

Avg Frequency

Most Common Topics

Array (25)String (12)Stack (11)Hash Table (9)Two Pointers (9)Math (8)Dynamic Programming (8)Sorting (8)

Companies Asking These Questions

Meta (8)Salesforce (6)Oracle (5)Infosys (5)Flipkart (4)Microsoft (3)

Problems in This Collection

#1EasyFrequency: 100%High Priority

Two Sum

Asked at Google

Array Hash Table

Rank

#3594MediumFrequency: 100%High Priority

Identify the Largest Outlier in an Array

Asked at Amazon

Array Hash Table Counting Enumeration

Rank

#3655MediumFrequency: 100%High Priority

Digit Operations to Make Two Integers Equal

Math Graph Heap (Priority Queue)Number Theory Shortest Path

Rank

#1371MediumFrequency: 100%High Priority

Minimum Remove to Make Valid Parentheses

Rank

#1352HardFrequency: 100%High Priority

Maximum Profit in Job Scheduling

Array Binary Search Dynamic Programming Sorting

Rank

#232EasyFrequency: 100%High Priority

Implement Queue using Stacks

Stack Design Queue

Rank

#3613MediumFrequency: 100%High Priority

Maximize Amount After Two Days of Conversions

Array String Depth-First Search Breadth-First Search Graph

Rank

#716HardFrequency: 100%High Priority

Max Stack

Linked List Stack Design Doubly-Linked List Ordered Set

Rank

#1085MediumFrequency: 100%High Priority

The Earliest Moment When Everyone Become Friends

Array Union Find Sorting

Rank

#392EasyFrequency: 100%High Priority

Is Subsequence

Two Pointers String Dynamic Programming

#10

Rank

#64MediumFrequency: 100%High Priority

Minimum Path Sum

Array Dynamic Programming Matrix

#11

Rank

#817EasyFrequency: 100%High Priority

Design HashMap

Asked at DoorDash

Array Hash Table Linked List Design Hash Function

#12

Rank

#322MediumFrequency: 100%High Priority

Coin Change

Array Dynamic Programming Breadth-First Search

#13

Rank

#2383EasyFrequency: 100%High Priority

Add Two Integers

#14

Rank

#42HardFrequency: 100%High Priority

Trapping Rain Water

Array Two Pointers Dynamic Programming Stack Monotonic Stack

#15

Rank

#3681MediumFrequency: 100%High Priority

Maximum Area Rectangle With Point Constraints I

Array Math Binary Indexed Tree Segment Tree Geometry+2 more

#16

Rank

#1056MediumFrequency: 100%High Priority

Capacity To Ship Packages Within D Days

Array Binary Search

#17

Rank

#694MediumFrequency: 98%High Priority

Number of Distinct Islands

Hash Table Depth-First Search Breadth-First Search Union Find Hash Function

#18

Rank

#314MediumFrequency: 97%High Priority

Binary Tree Vertical Order Traversal

Hash Table Tree Depth-First Search Breadth-First Search Sorting+1 more

#19

Rank

#227MediumFrequency: 96%High Priority

Basic Calculator II

Math String Stack

#20

Rank

#680EasyFrequency: 95%High Priority

Valid Palindrome II

Two Pointers String Greedy

#21

Rank

#833HardFrequency: 95%High Priority

Bus Routes

Array Hash Table Breadth-First Search

#22

Rank

#739MediumFrequency: 94%High Priority

Daily Temperatures

#23

Rank

#415EasyFrequency: 94%High Priority

Add Strings

Math String Simulation

#24

Rank

#957MediumFrequency: 94%High Priority

Minimum Add to Make Parentheses Valid

String Stack Greedy

#25

Rank

#2891MediumFrequency: 93%High Priority

Maximum Beauty of an Array After Applying Operation

Array Binary Search Sliding Window Sorting

#26

Rank

#152MediumFrequency: 93%High Priority

Maximum Product Subarray

#27

Rank

#2MediumFrequency: 93%High Priority

Add Two Numbers

Linked List Math Recursion

#28

Rank

#84HardFrequency: 93%High Priority

Largest Rectangle in Histogram

#29

Rank

#234EasyFrequency: 93%High Priority

Palindrome Linked List

Linked List Two Pointers Stack Recursion

#30

Rank

#3639MediumFrequency: 93%High Priority

Zero Array Transformation I

Array Prefix Sum

#31

Rank

#88EasyFrequency: 92%High Priority

Merge Sorted Array

Array Two Pointers Sorting

#32

Rank

#215MediumFrequency: 92%High Priority

Kth Largest Element in an Array

Array Divide and Conquer Sorting Heap (Priority Queue)Quickselect

#33

Rank

#19MediumFrequency: 92%High Priority

Remove Nth Node From End of List

Linked List Two Pointers

#34

Rank

#1790MediumFrequency: 91%High Priority

Lowest Common Ancestor of a Binary Tree III

Hash Table Two Pointers Tree Binary Tree

#35

Rank

#129MediumFrequency: 91%High Priority

Sum Root to Leaf Numbers

Tree Depth-First Search Binary Tree

#36

Rank

#1046MediumFrequency: 91%High Priority

Max Consecutive Ones III

Array Binary Search Sliding Window Prefix Sum

#37

Rank

#65HardFrequency: 91%High Priority

Valid Number

#38

Rank

#1423MediumFrequency: 91%High Priority

Maximum Number of Occurrences of a Substring

Hash Table String Sliding Window

#39

Rank

#122MediumFrequency: 90%High Priority

Best Time to Buy and Sell Stock II

Array Dynamic Programming Greedy

#40

Rank

#20EasyFrequency: 90%High Priority

Valid Parentheses

#41

Rank

#121EasyFrequency: 89%High Priority

Best Time to Buy and Sell Stock

#42

Rank

#136EasyFrequency: 89%High Priority

Single Number

Array Bit Manipulation

#43

Rank

#852MediumFrequency: 89%High Priority

Friends Of Appropriate Ages

Array Two Pointers Binary Search Sorting

#44

Rank

#146MediumFrequency: 88%High Priority

LRU Cache

Hash Table Linked List Design Doubly-Linked List

#45

Rank

#364MediumFrequency: 88%High Priority

Nested List Weight Sum II

Stack Depth-First Search Breadth-First Search

#46

Rank

#7MediumFrequency: 88%High Priority

Reverse Integer

#47

Rank

#6MediumFrequency: 88%High Priority

Zigzag Conversion

#48

Rank

#408EasyFrequency: 87%High Priority

Valid Word Abbreviation

Two Pointers String

#49

Rank

#912MediumFrequency: 87%High Priority

Random Pick with Weight