Quick Interview Prep - 25 Essential Problems

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Quick Interview Prep - 25 Essential Problems

Curated list of 25 must-know problems for last-minute interview preparation.

Total Problems

Easy

Medium

Hard

98%

Avg Frequency

Most Common Topics

Array (14)Hash Table (10)String (8)Sorting (8)Breadth-First Search (5)Design (5)Two Pointers (5)Heap (Priority Queue) (4)

Companies Asking These Questions

Meta (5)Oracle (3)Microsoft (2)Uber (2)Salesforce (2)DoorDash (2)

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

Asked at Microsoft

Math Graph Heap (Priority Queue)Number Theory Shortest Path

Rank

#1371MediumFrequency: 100%High Priority

Minimum Remove to Make Valid Parentheses

Asked at Meta

String Stack

Rank

#3638HardFrequency: 100%High Priority

Minimum Operations to Make Character Frequencies Equal

Asked at TikTok

Hash Table String Dynamic Programming Counting Enumeration

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

Asked at LinkedIn

Linked List Stack Design Doubly-Linked List Ordered Set

Rank

#49MediumFrequency: 100%High Priority

Group Anagrams

Asked at Oracle

Array Hash Table String Sorting

Rank

#71MediumFrequency: 100%High Priority

Simplify Path

Asked at Oracle

String Stack

Rank

#1306EasyFrequency: 100%High Priority

Minimum Absolute Difference

Asked at Oracle

Array Sorting

#10

Rank

#532MediumFrequency: 100%High Priority

K-diff Pairs in an Array

Asked at Salesforce

Array Hash Table Two Pointers Binary Search Sorting

#11

Rank

#1423MediumFrequency: 100%High Priority

Maximum Number of Occurrences of a Substring

Asked at Salesforce

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

Asked at Databricks

Array Binary Search Design Queue Data Stream

#17

Rank

#314MediumFrequency: 97%High Priority

Binary Tree Vertical Order Traversal

Asked at Meta

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

#18

Rank

#227MediumFrequency: 96%High Priority

Basic Calculator II

Asked at Meta

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

Asked at Meta

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

Asked at Databricks

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

Asked at Meta

Array Divide and Conquer Sorting Heap (Priority Queue)Quickselect

#25

Rank

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Turn Practice into Success

You've practiced with our quick interview prep - 25 essential problems. Now get AI assistance during your real interviews to solve these problems live and land your dream job.

Solve problems instantly

Boost confidence

Land your dream job

Start Free TrialNo credit card required View Pricing

Quick Interview Prep - 25 Essential Problems

Most Common Topics

Companies Asking These Questions

Problems in This Collection

Two Sum

Identify the Largest Outlier in an Array

Digit Operations to Make Two Integers Equal

Minimum Remove to Make Valid Parentheses

Minimum Operations to Make Character Frequencies Equal

Maximize Amount After Two Days of Conversions

Max Stack

Group Anagrams

Simplify Path

Minimum Absolute Difference

K-diff Pairs in an Array

Maximum Number of Occurrences of a Substring

Walls and Gates

Shortest Path in Binary Matrix

LRU Cache

Find Median from Data Stream

Design Hit Counter

Binary Tree Vertical Order Traversal

Basic Calculator II

Find K Closest Elements

Valid Palindrome II

Bus Routes

Design Tic-Tac-Toe

Merge Sorted Array

Kth Largest Element in an Array

Other Collections

Most Frequent Interview Questions

Top 100 Interview Questions

Beginner-Friendly Interview Questions

Advanced Interview Problems

System Design Interview Prep

Turn Practice into Success

Quick Interview Prep - 25 Essential Problems

Most Common Topics

Companies Asking These Questions

Problems in This Collection

Two Sum

Identify the Largest Outlier in an Array

Digit Operations to Make Two Integers Equal

Minimum Remove to Make Valid Parentheses

Minimum Operations to Make Character Frequencies Equal

Maximize Amount After Two Days of Conversions

Max Stack

Group Anagrams

Simplify Path

Minimum Absolute Difference

K-diff Pairs in an Array

Maximum Number of Occurrences of a Substring

Walls and Gates

Shortest Path in Binary Matrix

LRU Cache

Find Median from Data Stream

Design Hit Counter

Binary Tree Vertical Order Traversal

Basic Calculator II

Find K Closest Elements

Valid Palindrome II

Bus Routes

Design Tic-Tac-Toe

Merge Sorted Array

Kth Largest Element in an Array

Other Collections

Most Frequent Interview Questions

Top 100 Interview Questions

Beginner-Friendly Interview Questions

Advanced Interview Problems

System Design Interview Prep

Turn Practice into Success