Quick Interview Prep - 25 Essential Problems

Array Binary Search Dynamic Programming Sorting

String Stack

Rank

#1352HardFrequency: 100%High Priority

Maximum Profit in Job Scheduling

Asked at Apple

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

Asked at LinkedIn

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

Asked at Salesforce

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

Asked at Airbnb

Array Dynamic Programming Breadth-First Search

#13

Rank

#2383EasyFrequency: 100%High Priority

Add Two Integers

Math

#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

Asked at Infosys

Array Math Binary Indexed Tree Segment Tree Geometry+2 more

#16

Rank

#1056MediumFrequency: 100%High Priority

Capacity To Ship Packages Within D Days

Asked at Databricks

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

Array Stack Monotonic Stack

#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

Other Collections

Most Frequent Interview Questions

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

Beginner-Friendly Interview Questions

Easy to medium difficulty problems perfect for interview preparation beginners.

75 problems →

Advanced Interview Problems

Challenging hard problems asked at top-tier tech companies for senior positions.

Array (13)String (7)Stack (7)Hash Table (6)Math (5)Dynamic Programming (5)Breadth-First Search (5)Sorting (4)

System Design Interview Prep

Coding problems that help build system design thinking and scalability concepts.

60 problems →

Turn Practice into Success

Get AI assistance during your real interviews to solve these problems live and land your dream job.

Get Started Free

No credit card required

Quick Interview Prep - 25 Essential Problems

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

Total Problems

Easy

Medium

Hard

99%

Avg Frequency

Most Common Topics

Companies Asking These Questions

Meta (4)Oracle (3)TikTok (2)Uber (2)Flipkart (2)PayPal (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

Array Binary Search Dynamic Programming Sorting

String Stack

Rank

#1352HardFrequency: 100%High Priority

Maximum Profit in Job Scheduling

Asked at Apple

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

Asked at LinkedIn

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

Asked at Salesforce

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

Asked at Airbnb

Array Dynamic Programming Breadth-First Search

#13

Rank

#2383EasyFrequency: 100%High Priority

Add Two Integers

Math

#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

Asked at Infosys

Array Math Binary Indexed Tree Segment Tree Geometry+2 more

#16

Rank

#1056MediumFrequency: 100%High Priority

Capacity To Ship Packages Within D Days

Asked at Databricks

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

Array Stack Monotonic Stack

#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

Other Collections

Most Frequent Interview Questions

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

Beginner-Friendly Interview Questions

Easy to medium difficulty problems perfect for interview preparation beginners.

75 problems →

Advanced Interview Problems

Challenging hard problems asked at top-tier tech companies for senior positions.