Most Frequent Interview Questions

Hash Table String Dynamic Programming Counting Enumeration

String Stack

Rank

#3638HardFrequency: 100%High Priority

Minimum Operations to Make Character Frequencies Equal

Asked at TikTok

Rank

#3613MediumFrequency: 100%High Priority

Maximize Amount After Two Days of Conversions

Asked at Uber

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

#49MediumFrequency: 100%High Priority

Group Anagrams

Array Hash Table String Sorting

Rank

#71MediumFrequency: 100%High Priority

Simplify Path

String Stack

Rank

#1306EasyFrequency: 100%High Priority

Minimum Absolute Difference

Array Sorting

#10

Rank

#532MediumFrequency: 100%High Priority

K-diff Pairs in an Array

Array Hash Table Two Pointers Binary Search Sorting

#11

Rank

#1423MediumFrequency: 100%High Priority

Maximum Number of Occurrences of a Substring

Hash Table String Sliding Window

#12

Rank

#286MediumFrequency: 100%High Priority

Walls and Gates

Asked at DoorDash

Array Breadth-First Search Matrix

#13

Rank

#1171MediumFrequency: 100%High Priority

Shortest Path in Binary Matrix

Asked at Airbnb

Array Breadth-First Search Matrix

#14

Rank

#146MediumFrequency: 100%High Priority

LRU Cache

Asked at Flipkart

Hash Table Linked List Design Doubly-Linked List

#15

Rank

#295HardFrequency: 100%High Priority

Find Median from Data Stream

Asked at PayPal

Two Pointers Design Sorting Heap (Priority Queue)Data Stream

#16

Rank

#362MediumFrequency: 100%High Priority

Design Hit Counter

Array Binary Search Design Queue Data Stream

#17

Rank

#314MediumFrequency: 97%High Priority

Binary Tree Vertical Order Traversal

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

#18

Rank

#227MediumFrequency: 96%High Priority

Basic Calculator II

Math String Stack

#19

Rank

#658MediumFrequency: 96%High Priority

Find K Closest Elements

Asked at DoorDash

Array Two Pointers Binary Search Sliding Window Sorting+1 more

#20

Rank

#680EasyFrequency: 95%High Priority

Valid Palindrome II

Two Pointers String Greedy

#21

Rank

#833HardFrequency: 95%High Priority

Bus Routes

Asked at Uber

Array Hash Table Breadth-First Search

#22

Rank

#348MediumFrequency: 93%High Priority

Design Tic-Tac-Toe

Array Hash Table Design Matrix Simulation

#23

Rank

#88EasyFrequency: 92%High Priority

Merge Sorted Array

Asked at Microsoft

Array Two Pointers Sorting

#24

Rank

#215MediumFrequency: 92%High Priority

Kth Largest Element in an Array

Array Divide and Conquer Sorting Heap (Priority Queue)Quickselect

#25

Rank

#1790MediumFrequency: 91%High Priority

Lowest Common Ancestor of a Binary Tree III

Hash Table Two Pointers Tree Binary Tree

#26

Rank

#364MediumFrequency: 88%High Priority

Nested List Weight Sum II

Stack Depth-First Search Breadth-First Search

#27

Rank

#1046MediumFrequency: 88%High Priority

Max Consecutive Ones III

Array Binary Search Sliding Window Prefix Sum

#28

Rank

#200MediumFrequency: 88%High Priority

Number of Islands

Array Depth-First Search Breadth-First Search Union Find Matrix

#29

Rank

#300MediumFrequency: 88%High Priority

Longest Increasing Subsequence

Array Binary Search Dynamic Programming

#30

Rank

#460HardFrequency: 88%High Priority

LFU Cache

Hash Table Linked List Design Doubly-Linked List

#31

Rank

#647MediumFrequency: 88%High Priority

Palindromic Substrings

Two Pointers String Dynamic Programming

#32

Rank

#408EasyFrequency: 87%High Priority

Valid Word Abbreviation

Two Pointers String

#33

Rank

#912MediumFrequency: 87%High Priority

Random Pick with Weight

Array Math Binary Search Prefix Sum Randomized

#34

Rank

#125EasyFrequency: 87%High Priority

Valid Palindrome

Two Pointers String

#35

Rank

#206EasyFrequency: 87%High Priority

Reverse Linked List

Linked List Recursion

#36

Rank

#238MediumFrequency: 87%High Priority

Product of Array Except Self

Array Prefix Sum

#37

Rank

#322MediumFrequency: 87%High Priority

Coin Change

Array Dynamic Programming Breadth-First Search

#38

Rank

#1478MediumFrequency: 87%High Priority

Maximum Number of Events That Can Be Attended

Array Greedy Sorting Heap (Priority Queue)

#39

Rank

#621MediumFrequency: 85%High Priority

Task Scheduler

Asked at Amazon

Array Hash Table Greedy Sorting Heap (Priority Queue)+1 more

#40

Rank

#50MediumFrequency: 85%High Priority

Pow(x, n)

Math Recursion

#41

Rank

#162MediumFrequency: 85%High Priority

Find Peak Element

Hash Table String Sliding Window

Array Binary Search

#42

Rank

#3MediumFrequency: 84%High Priority

Longest Substring Without Repeating Characters

Asked at Microsoft

#43

Rank

#339MediumFrequency: 84%High Priority

Nested List Weight Sum

Depth-First Search Breadth-First Search

#44

Rank

#366MediumFrequency: 84%High Priority

Find Leaves of Binary Tree

Tree Depth-First Search Binary Tree

#45

Rank

#8MediumFrequency: 84%High Priority

String to Integer (atoi)

String

#46

Rank

#198MediumFrequency: 84%High Priority

House Robber

Array Dynamic Programming

#47

Rank

#213MediumFrequency: 84%High Priority

House Robber II

Array Dynamic Programming

#48

Rank

#752MediumFrequency: 84%High Priority

IP to CIDR