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Entry-Level Software Engineer Interview Questions

These questions are tailored for aspiring software engineers, offering essential interview prep and guided practice to help you build confidence and showcase your foundational skills effectively.

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Entry-level software engineer interviews focus on your grasp of programming fundamentals, problem-solving ability, and understanding of how software systems work. In this set of interview questions, you’ll tackle problems and scenarios that reflect the types of challenges commonly faced by new software engineers. You’ll practice writing and debugging functions in your preferred programming language, solving algorithmic problems involving arrays, strings, hash maps, and recursion, and analyzing time and space complexity. The questions also cover foundational technical knowledge, such as explaining core concepts like HTTP, databases, and APIs. Additionally, you’ll be asked to reason through simple system design tasks, like structuring a basic to-do app or implementing a queue—helping you develop both technical clarity and practical design thinking. Each question is designed to reinforce your understanding of computer science fundamentals and help you build fluency in solving problems under time constraints.

Entry-level software engineer interviews focus on your grasp of programming fundamentals, problem-solving ability, and understan...Show More

WHAT YOU'LL LEARN

Strategies to approach entry-level software engineer interview questions with clarity and a solid understanding of the basics.

Pattern-based problem solving using techniques like two pointers, sliding windows, and hash maps.

Methods to clearly communicate your thinking, improve your code, and reflect on time-space trade-offs.

Key programming principles include object-oriented design, databases, APIs, and version control.

Guidance for succeeding in behavioral interviews and communicating technical decisions.

Ways to practice effectively and grow your confidence through consistent, focused preparation.

Strategies to approach entry-level software engineer interview questions with clarity and a solid understanding of the basics.

Content

763 Lessons398 Quizzes397 Challenges

Getting Started

2 Lessons

Course Overview

Who Should Take This Course

Two Pointers

26 Lessons

Introduction to Two Pointers

Valid Palindrome

Solution: Valid Palindrome

3Sum

Solution: 3Sum

Remove Nth Node from End of List

Solution: Remove Nth Node from End of List

Sort Colors

Solution: Sort Colors

Reverse Words in a String

Solution: Reverse Words in a String

Valid Word Abbreviation

Solution: Valid Word Abbreviation

Strobogrammatic Number

Solution: Strobogrammatic Number

Minimum Number of Moves to Make Palindrome

Solution: Minimum Number of Moves to Make Palindrome

Next Palindrome Using Same Digits

Solution: Next Palindrome Using Same Digits

Lowest Common Ancestor of a Binary Tree III

Solution: Lowest Common Ancestor of a Binary Tree III

Count Pairs Whose Sum is Less than Target

Solution: Count Pairs Whose Sum is Less than Target

Count Subarrays With Fixed Bounds

Solution: Count Subarrays With Fixed Bounds

Valid Palindrome II

Two Pointers

Mock Interview

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Fast and Slow Pointers

21 Lessons

Introduction to Fast and Slow Pointers

Happy Number

Solution: Happy Number

Linked List Cycle

Solution: Linked List Cycle

Middle of the Linked List

Solution: Middle of the Linked List

Circular Array Loop

Solution: Circular Array Loop

Find the Duplicate Number

Solution: Find the Duplicate Number

Palindrome Linked List

Solution: Palindrome Linked List

Maximum Twin Sum of a Linked List

Solution: Maximum Twin Sum of a Linked List

Split a Circular Linked List

Solution: Split a Circular Linked List

Linked List Cycle III

Solution: Linked List Cycle III

Linked List Cycle IV

Solution: Linked List Cycle IV

Fast and Slow Pointers

Mock Interview

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Sliding Window

29 Lessons

Introduction to Sliding Window

Repeated DNA Sequences

Solution: Repeated DNA Sequences

Sliding Window Maximum

Solution: Sliding Window Maximum

Minimum Window Subsequence

Solution: Minimum Window Subsequence

Longest Repeating Character Replacement

Solution: Longest Repeating Character Replacement

Minimum Window Substring

Solution: Minimum Window Substring

Longest Substring without Repeating Characters

Solution: Longest Substring without Repeating Characters

Minimum Size Subarray Sum

Solution: Minimum Size Subarray Sum

Maximum Average Subarray I

Solution: Maximum Average Subarray I

Diet Plan Performance

Solution: Diet Plan Performance

Fruit Into Baskets

Solution: Fruit Into Baskets

Contains Duplicate II

Solution: Contains Duplicate II

Frequency of the Most Frequent Element

Solution: Frequency of the Most Frequent Element

Subarrays with K Different Integers

Solution: Subarrays with K Different Integers

Count Subarrays With Score Less Than K

Solution: Count Subarrays With Score Less Than K

Sliding Window

Mock Interview

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Merge Intervals

14 Lessons

Introduction to Merge Intervals

Merge Intervals

Solution: Merge Intervals

Insert Interval

Solution: Insert Interval

Interval List Intersections

Solution: Interval List Intersections

Employee Free Time

Solution: Employee Free Time

Count Days Without Meetings

Solution: Count Days Without Meetings

Remove Covered Intervals

Solution: Remove Covered Intervals

Meeting Rooms II

In-Place Manipulation of a Linked List

24 Lessons

Introduction to In-Place Manipulation of a Linked List

Reverse Linked List

Solution: Reverse Linked List

Reverse Nodes in k-Group

Solution: Reverse Nodes in k-Group

Reverse Linked List II

Solution: Reverse Linked List II

Reorder List

Solution: Reorder List

Swapping Nodes in a Linked List

Solution: Swapping Nodes in a Linked List

Reverse Nodes in Even Length Groups

Solution: Reverse Nodes in Even Length Groups

Remove Duplicates from Sorted List

Solution: Remove Duplicates from Sorted List

Remove Linked List Elements

Solution: Remove Linked List Elements

Split Linked List in Parts

Solution: Split Linked List in Parts

Delete N Nodes After M Nodes of a Linked List

Solution: Delete N Nodes After M Nodes of a Linked List

Insert into a Sorted Circular Linked List

Solution: Insert into a Sorted Circular Linked List

Swap Nodes in Pairs

Heaps

23 Lessons

Introduction to Heaps

IPO

Solution: IPO

Find Median from Data Stream

Solution: Find Median from Data Stream

Sliding Window Median

Solution: Sliding Window Median

Schedule Tasks on Minimum Machines

Solution: Schedule Tasks on Minimum Machines

Meeting Rooms III

Solution: Meeting Rooms III

Largest Number After Digit Swaps by Parity

Solution: Largest Number After Digit Swaps by Parity

Find Right Interval

Solution: Find Right Interval

Minimum Cost to Connect Sticks

Solution: Minimum Cost to Connect Sticks

Longest Happy String

Solution: Longest Happy String

Maximum Average Pass Ratio

Solution: Maximum Average Pass Ratio

The Number of the Smallest Unoccupied Chair

Solution: The Number of the Smallest Unoccupied Chair

Heaps

Mock Interview

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K-way merge

15 Lessons

Introduction to K-way Merge

Merge Sorted Array

Solution: Merge Sorted Array

Kth Smallest Number in M Sorted Lists

Solution: Kth Smallest Number in M Sorted Lists

Find K Pairs with Smallest Sums

Solution: Find K Pairs with Smallest Sums

Merge K Sorted Lists

Solution: Merge K Sorted Lists

Kth Smallest Element in a Sorted Matrix

Solution: Kth Smallest Element in a Sorted Matrix

Kth Smallest Prime Fraction

Solution: Kth Smallest Prime Fraction

Super Ugly Number

Solution: Super Ugly Number

Top K Elements

33 Lessons

Introduction to Top K Elements

Kth Largest Element in a Stream

Solution: Kth Largest Element in a Stream

Reorganize String

Solution: Reorganize String

K Closest Points to Origin

Solution: K Closest Points to Origin

Top K Frequent Elements

Solution: Top K Frequent Elements

Kth Largest Element in an Array

Solution: Kth Largest Element in an Array

Third Maximum Number

Solution: Third Maximum Number

Find Subsequence of Length K with the Largest Sum

Solution: Find Subsequence of Length K with the Largest Sum

Minimum Cost to Hire K Workers

Solution: Minimum Cost to Hire K Workers

Maximal Score After Applying K Operations

Solution: Maximal Score After Applying K Operations

Find the Kth Largest Integer in the Array

Solution: Find the Kth Largest Integer in the Array

Maximum Performance of a Team

Solution: Maximum Performance of a Team

Smallest Range Covering Elements from K Lists

Solution: Smallest Range Covering Elements from K Lists

K Maximum Sum Combinations From Two Arrays

Solution: K Maximum Sum Combinations From Two Arrays

K Empty Slots

Solution: K Empty Slots

Maximum Product After K Increments

Solution: Maximum Product After K Increments

Find the K-Sum of an Array

Solution: Find the K-Sum of an Array

10.

Modified Binary Search

28 Lessons

Introduction to Modified Binary Search

Binary Search

Solution: Binary Search

Search in Rotated Sorted Array

Solution: Search in Rotated Sorted Array

First Bad Version

Solution: First Bad Version

Random Pick with Weight

Solution: Random Pick with Weight

Find K Closest Elements

Solution: Find K Closest Elements

Single Element in a Sorted Array

Solution: Single Element in a Sorted Array

Maximum Value at a Given Index in a Bounded Array

Solution: Maximum Value at a Given Index in a Bounded Array

The K Weakest Rows in a Matrix

Solution: The K Weakest Rows in a Matrix

Split Array Largest Sum

Solution: Split Array Largest Sum

Find Minimum in Rotated Sorted Array II

Solution: Find Minimum in Rotated Sorted Array II

Maximum Running Time of N Computers

Solution: Maximum Running Time of N Computers

Minimize Max Distance to Gas Station

Solution: Minimize Max Distance to Gas Station

Divide Chocolate

Solution: Divide Chocolate

Search in Rotated Sorted Array II

Modified Binary Search

Mock Interview

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11.

Subsets

14 Lessons

Introduction to Subsets

Subsets

Solution: Subsets

Permutations

Solution: Permutations

Letter Combinations of a Phone Number

Solution: Letter Combinations of a Phone Number

Generate Parentheses

Solution: Generate Parentheses

Letter Case Permutation

Solution: Letter Case Permutation

Letter Tile Possibilities

Solution: Letter Tile Possibilities

Find K-Sum Subsets

12.

Greedy Techniques

31 Lessons

Introduction to Greedy Techniques

Jump Game

Solution: Jump Game

Boats to Save People

Solution: Boats to Save People

Gas Station

Solution: Gas Station

Two City Scheduling

Solution: Two City Scheduling

Minimum Number of Refueling Stops

Solution: Minimum Number of Refueling Stops

Largest Palindromic Number

Solution: Largest Palindromic Number

Assign Cookies

Solution: Assign Cookies

Rearranging Fruits

Solution: Rearranging Fruits

Number of Steps to Reduce a Binary Number to One

Solution: Number of Steps to Reduce a Binary Number to One

Maximum Swap

Solution: Maximum Swap

Can Place Flowers

Solution: Can Place Flowers

Largest Odd Number in String

Solution: Largest Odd Number in String

Candy

Solution: Candy

Minimum Replacements to Sort the Array

Solution: Minimum Replacements to Sort the Array

Jump Game II

Best Time to Buy and Sell Stock

13.

Backtracking

27 Lessons

Introduction to Backtracking

N-Queens II

Solution: N-Queens II

Word Search

Solution: Word Search

House Robber III

Solution: House Robber III

Restore IP Addresses

Solution: Restore IP Addresses

Flood Fill

Solution: Flood Fill

Minimum Moves to Spread Stones Over Grid

Solution: Minimum Moves to Spread Stones Over Grid

Binary Tree Paths

Solution: Binary Tree Paths

Binary Watch

Solution: Binary Watch

Optimal Account Balancing

Solution: Optimal Account Balancing

Split a String Into the Max Number of Unique Substrings

Solution: Split a String Into the Max Number of Unique Substrings

All Paths From Source to Target

Solution: All Paths From Source to Target

Remove Invalid Parentheses

Solution: Remove Invalid Parentheses

Sudoku Solver

Matchsticks to Square

14.

Dynamic Programming

36 Lessons

Introduction to Dynamic Programming

0/1 Knapsack

Solution: 0/1 Knapsack

Coin Change

Solution: Coin Change

N-th Tribonacci Number

Solution: N-th Tribonacci Number

Partition Equal Subset Sum

Solution: Partition Equal Subset Sum

Counting Bits

Solution: Counting Bits

01 Matrix

Solution: 01 Matrix

House Robber II

Solution: House Robber II

Maximum Product Subarray

Solution: Maximum Product Subarray

Combination Sum

Solution: Combination Sum

Word Break

Solution: Word Break

Palindromic Substrings

Solution: Palindromic Substrings

Longest Common Subsequence

Solution: Longest Common Subsequence

Word Break II

Solution: Word Break II

Decode Ways

Solution: Decode Ways

Count the Number of Good Subsequences

Solution: Count the Number of Good Subsequences

Binary Tree Cameras

Solution: Binary Tree Cameras

Number of Ways to Form Target String Given a Dictionary

Solution: Number of Ways to Form Target String Given a Dictionary

Climbing Stairs

Dynamic Programming

Mock Interview

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15.

Cyclic Sort

12 Lessons

Introduction to Cyclic Sort

Cyclic Sort

Solution: Cyclic Sort

Missing Number

Solution: Missing Number

First Missing Positive

Solution: First Missing Positive

Find the Corrupt Pair

Solution: Find the Corrupt Pair

Sort Array By Parity II

Solution: Sort Array By Parity II

Find the First K Missing Positive Numbers

16.

Topological Sort

16 Lessons

Introduction to Topological Sort

Compilation Order

Solution: Compilation Order

Alien Dictionary

Solution: Alien Dictionary

Verifying an Alien Dictionary

Solution: Verifying an Alien Dictionary

Course Schedule II

Solution: Course Schedule II

Course Schedule

Solution: Course Schedule

Build a Matrix with Conditions

Solution: Build a Matrix with Conditions

Longest Path With Different Adjacent Characters

Solution: Longest Path With Different Adjacent Characters

Find All Possible Recipes from Given Supplies

Topological Sort

Mock Interview

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17.

Sort and Search

31 Lessons

Introduction to Sort and Search

Find the Distance Value Between Two Arrays

Solution: Find the Distance Value Between Two Arrays

Longest Subsequence With Limited Sum

Solution: Longest Subsequence With Limited Sum

Find Target Indices After Sorting Array

Solution: Find Target Indices After Sorting Array

Count Pairs in Two Arrays

Solution: Count Pairs in Two Arrays

Valid Triangle Number

Solution: Valid Triangle Number

Minimum Operations to Make All Array Elements Equal

Solution: Minimum Operations to Make All Array Elements Equal

Sum of Mutated Array Closest to Target

Solution: Sum of Mutated Array Closest to Target

Range Sum of Sorted Subarray Sums

Solution: Range Sum of Sorted Subarray Sums

Magnetic Force Between Two Balls

Solution: Magnetic Force Between Two Balls

Find K-th Smallest Pair Distance

Solution: Find K-th Smallest Pair Distance

Minimum Space Wasted from Packaging

Solution: Minimum Space Wasted from Packaging

Russian Doll Envelopes

Solution: Russian Doll Envelopes

Put Marbles in Bags

Solution: Put Marbles in Bags

H-Index

Solution: H-Index

Two Sum Less Than K

Maximum Number of Integers to Choose from a Range I

18.

Matrices

31 Lessons

Introduction to Matrices

Set Matrix Zeroes

Solution: Set Matrix Zeroes

Rotate Image

Solution: Rotate Image

Spiral Matrix

Solution: Spiral Matrix

Where Will the Ball Fall

Solution: Where Will the Ball Fall

Transpose Matrix

Solution: Transpose Matrix

Count Negative Numbers in a Sorted Matrix

Solution: Count Negative Numbers in a Sorted Matrix

Minimum Time Takes to Reach Destination Without Drowning

Solution:Minimum Time Takes to Reach Destination Without Drowning

Smallest Rectangle Enclosing Black Pixels

Solution: Smallest Rectangle Enclosing Black Pixels

Island Perimeter

Solution: Island Perimeter

Convert 1D Array Into 2D Array

Solution: Convert 1D Array Into 2D Array

Spiral Matrix II

Solution: Spiral Matrix II

Flip Columns For Maximum Number of Equal Rows

Solution: Flip Columns For Maximum Number of Equal Rows

Number of Spaces Cleaning Robot Cleaned

Solution: Number of Spaces Cleaning Robot Cleaned

Minimize Maximum Value in a Grid

Solution: Minimize Maximum Value in a Grid

Kth Smallest Number in Multiplication Table

Solution: Kth Smallest Number in Multiplication Table

19.

Stacks

26 Lessons

Introduction to Stacks

Basic Calculator

Solution: Basic Calculator

Remove All Adjacent Duplicates In String

Solution: Remove All Adjacent Duplicates In String

Minimum Remove to Make Valid Parentheses

Solution: Minimum Remove to Make Valid Parentheses

Exclusive Time of Functions

Solution: Exclusive Time of Functions

Flatten Nested List Iterator

Solution: Flatten Nested List Iterator

Implement Queue Using Stacks

Solution: Implement Queue Using Stacks

Daily Temperatures

Solution: Daily Temperatures

Decode String

Solution: Decode String

Minimum String Length After Removing Substrings

Solution: Minimum String Length After Removing Substrings

Number of Valid Subarrays

Solution: Number of Valid Subarrays

Number of Visible People in a Queue

Solution: Number of Visible People in a Queue

Parsing a Boolean Expression

Solution: Parsing a Boolean Expression

Valid Parentheses

20.

Graphs

31 Lessons

Introduction to Graphs

Network Delay Time

Solution: Network Delay Time

Paths in Maze That Lead to Same Room

Solution: Paths in Maze That Lead to Same Room

Clone Graph

Solution: Clone Graph

Graph Valid Tree

Solution: Graph Valid Tree

Bus Routes

Solution: Bus Routes

Reconstruct Itinerary

Solution: Reconstruct Itinerary

Find the Town Judge

Solution: Find the Town Judge

Find Center of Star Graph

Solution: Find Center of Star Graph

Lucky Numbers in a Matrix

Solution: Lucky Numbers in a Matrix

Path with Maximum Probability

Solution: Path with Maximum Probability

Tree Diameter

Solution: Tree Diameter

Reorder Routes to Make All Paths Lead to the City Zero

Solution: Reorder Routes to Make All Paths Lead to the City Zero

Minimum Cost to Make at Least One Valid Path in a Grid

Solution: Minimum Cost to Make at Least One Valid Path in a Grid

Longest Cycle in a Graph

Solution: Longest Cycle in a Graph

Shortest Cycle in a Graph

Solution: Shortest Cycle in a Graph

Graphs

Mock Interview

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21.

Tree Depth-First Search

31 Lessons

Introduction to Tree Depth-First Search

Flatten Binary Tree to Linked List

Solution: Flatten Binary Tree to Linked List

Diameter of Binary Tree

Solution: Diameter of Binary Tree

Serialize and Deserialize Binary Tree

Solution: Serialize and Deserialize Binary Tree

Invert Binary Tree

Solution: Invert Binary Tree

Binary Tree Maximum Path Sum

Solution: Binary Tree Maximum Path Sum

Convert Sorted Array to Binary Search Tree

Solution: Convert Sorted Array to Binary Search Tree

Build Binary Tree from Preorder and Inorder Traversal

Solution: Build Binary Tree from Preorder and Inorder Traversal

Binary Tree Right Side View

Solution: Binary Tree Right Side View

Lowest Common Ancestor of a Binary Tree

Solution: Lowest Common Ancestor of a Binary Tree

Validate Binary Search Tree

Solution: Validate Binary Search Tree

Nested List Weight Sum II

Solution: Nested List Weight Sum II

Inorder Successor in BST

Solution: Inorder Successor in BST

Height of Binary Tree After Subtree Removal Queries

Solution: Height of Binary Tree After Subtree Removal Queries

Delete Nodes And Return Forest

Solution: Delete Nodes And Return Forest

Maximum Depth of Binary Tree

Kth Smallest Element in a BST

22.

Tree Breadth-First Search

20 Lessons

Introduction to Tree Breadth-First Search

Binary Tree Level Order Traversal

Solution: Binary Tree Level Order Traversal

Binary Tree Zigzag Level Order Traversal

Solution: Binary Tree Zigzag Level Order Traversal

Populating Next Right Pointers in Each Node

Solution: Populating Next Right Pointers in Each Node

Vertical Order Traversal of a Binary Tree

Solution: Vertical Order Traversal of a Binary Tree

Symmetric Tree

Solution: Symmetric Tree

Word Ladder

Solution: Word Ladder

Two Sum IV – Input Is a BST

Solution: Two Sum IV – Input Is a BST

Find Minimum Diameter After Merging Two Trees

Solution: Find Minimum Diameter After Merging Two Trees

Closest Node to Path in Tree

Solution: Closest Node to Path in Tree

Connect All Siblings of a Binary Tree

Tree Breadth First Search

Mock Interview

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23.

Trie

22 Lessons

Introduction to Trie

Implement Trie (Prefix Tree)

Solution: Implement Trie (Prefix Tree)

Search Suggestions System

Solution: Search Suggestions System

Replace Words

Solution: Replace Words

Design Add and Search Words Data Structure

Solution: Design Add and Search Words Data Structure

Word Search II

Solution: Word Search II

Top K Frequent Words

Solution: Top K Frequent Words

Longest Common Prefix

Solution: Longest Common Prefix

Index Pairs of a String

Solution: Index Pairs of a String

K-th Smallest in Lexicographical Order

Solution: K-th Smallest in Lexicographical Order

Palindrome Pairs

Solution: Palindrome Pairs

Lexicographical Numbers

24.

Hash Maps

36 Lessons

Introduction to Hash Maps

Design HashMap

Solution: Design HashMap

Fraction to Recurring Decimal

Solution: Fraction to Recurring Decimal

Logger Rate Limiter

Solution: Logger Rate Limiter

Next Greater Element I

Solution: Next Greater Element I

Isomorphic Strings

Solution: Isomorphic Strings

Find Duplicate File in System

Solution: Find Duplicate File in System

Dot Product of Two Sparse Vectors

Solution: Dot Product of Two Sparse Vectors

High Five

Solution: High Five

Bulls and Cows

Solution: Bulls and Cows

Custom Sort String

Solution: Custom Sort String

Number of Distinct Islands

Solution: Number of Distinct Islands

Number of Wonderful Substrings

Solution: Number of Wonderful Substrings

Total Appeal of a String

Solution: Total Appeal of a String

Continuous Subarray Sum

Solution: Continuous Subarray Sum

Unique Number of Occurrences

Solution: Unique Number of Occurrences

Longest Happy Prefix

Solution: Longest Happy Prefix

Find Longest Self-Contained Substring

Solution: Find Longest Self-Contained Substring

Longest Palindrome

25.

Knowing What to Track

30 Lessons

Introduction to Knowing What to Track

Palindrome Permutation

Solution: Palindrome Permutation

Valid Anagram

Solution: Valid Anagram

Design Tic-Tac-Toe

Solution: Design Tic-Tac-Toe

Group Anagrams

Solution: Group Anagrams

Maximum Frequency Stack

Solution: Maximum Frequency Stack

First Unique Character in a String

Solution: First Unique Character in a String

Find All Anagrams in a String

Solution: Find All Anagrams in a String

Longest Palindrome by Concatenating Two-Letter Words

Solution: Longest Palindrome by Concatenating Two-Letter Words

Rank Teams by Votes

Solution: Rank Teams by Votes

Pairs of Songs With Total Durations Divisible by 60

Solution: Pairs of Songs With Total Durations Divisible by 60

Minimum Number of Pushes to Type Word II

Solution: Minimum Number of Pushes to Type Word II

Task Scheduler

Solution: Task Scheduler

Count Anagrams

Solution: Count Anagrams

Divide Array Into Increasing Sequences

Solution: Divide Array Into Increasing Sequences

Ransom Note

26.

Union Find

22 Lessons

Introduction to Union Find

Redundant Connection

Solution: Redundant Connection

Number of Islands

Solution: Number of Islands

Most Stones Removed with Same Row or Column

Solution: Most Stones Removed with Same Row or Column

Longest Consecutive Sequence

Solution: Longest Consecutive Sequence

Last Day Where You Can Still Cross

Solution: Last Day Where You Can Still Cross

Regions Cut by Slashes

Solution: Regions Cut by Slashes

Accounts Merge

Solution: Accounts Merge

Minimize Malware Spread

Solution: Minimize Malware Spread

Find if Path Exists in Graph

Solution: Find if Path Exists in Graph

The Skyline Problem

Solution: The Skyline Problem

Evaluate Division

Union Find

Mock Interview

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27.

Custom Data Structures

26 Lessons

Introduction to Custom Data Structures

Snapshot Array

Solution: Snapshot Array

Time Based Key-Value Store

Solution: Time Based Key-Value Store

LRU Cache

Solution: LRU Cache

Insert Delete GetRandom O(1)

Solution: Insert Delete GetRandom O(1)

Min Stack

Solution: Min Stack

Range Module

Solution: Range Module

Shortest Word Distance II

Solution: Shortest Word Distance II

Design HashSet

Solution: Design HashSet

Max Stack

Solution: Max Stack

Moving Average from Data Stream

Solution: Moving Average from Data Stream

Two Sum III - Data structure design

Solution: Two Sum III - Data structure design

Range Sum Query - Immutable

Solution: Range Sum Query - Immutable

LFU Cache

28.

Bitwise Manipulation

30 Lessons

Introduction to Bitwise Manipulation

Find the Difference

Solution: Find the Difference

Complement of Base 10 Integer

Solution: Complement of Base 10 Integer

Flipping an Image

Solution: Flipping an Image

Single Number

Solution: Single Number

Single Number II

Solution: Single Number II

Encode and Decode Strings

Solution: Encode and Decode Strings

Sum of All Subset XOR Totals

Solution: Sum of All Subset XOR Totals

Find The K-th Lucky Number

Solution: Find The K-th Lucky Number

Minimum Number of K Consecutive Bit Flips

Solution: Minimum Number of K Consecutive Bit Flips

Find the Longest Substring Having Vowels in Even Counts

Solution: Find the Longest Substring Having Vowels in Even Counts

Count Triplets That Can Form Two Arrays of Equal XOR

Solution: Count Triplets That Can Form Two Arrays of Equal XOR

Longest Subarray With Maximum Bitwise AND

Solution: Longest Subarray With Maximum Bitwise AND

Minimum One Bit Operations to Make Integers Zero

Solution: Minimum One Bit Operations to Make Integers Zero

Triples with Bitwise AND Equal To Zero

Solution: Triples with Bitwise AND Equal To Zero

Reverse Bits

29.

Math and Geometry

35 Lessons

Introduction to Math and Geometry

Check If It Is a Straight Line

Solution: Check If It Is a Straight Line

Minimum Cuts to Divide a Circle

Solution: Minimum Cuts to Divide a Circle

Rectangle Overlap

Solution: Rectangle Overlap

Minimum Time Visiting All Points

Solution: Minimum Time Visiting All Points

Reverse Integer

Solution: Reverse Integer

Valid Square

Solution: Valid Square

Rectangle Area

Solution: Rectangle Area

Minimum Area Rectangle

Solution: Minimum Area Rectangle

Maximum Area Rectangle With Point Constraints I

Solution: Maximum Area Rectangle With Point Constraints I

Convex Polygon

Solution: Convex Polygon

Queries on Number of Points Inside a Circle

Solution: Queries on Number of Points Inside a Circle

Max Points on a Line

Solution: Max Points on a Line

Maximum Number of Visible Points

Solution: Maximum Number of Visible Points

Minimize Manhattan Distances

Solution: Minimize Manhattan Distances

Self Crossing

Solution: Self Crossing

Erect the Fence

Solution: Erect the Fence

Minimum Number of Lines to Cover Points

Detonate the Maximum Bombs

30.

Challenge Yourself

40 Lessons

Challenge Yourself: Introduction

Shortest Bridge

Number of Connected Components in an Undirected Graph

Median of Two Sorted Arrays

Pacific Atlantic Water Flow

Contains Duplicate

Maximum Subarray

Two Sum

Find Minimum in Rotated Sorted Array

Non-overlapping Intervals

Meeting Rooms

Largest Rectangle in Histogram

Subtree of Another Tree

Sort List

Number of 1 Bits

Container with Most Water

Evaluate Reverse Polish Notation

4Sum

Loud and Rich

Product of Array Except Self

Longest Increasing Subsequence

Sum of Two Integers

Majority Element

Unique Paths

Longest Palindromic Substring

Permutations II

Number of Provinces

Linked List Cycle II

Minimum Flips to Make the Binary String Alternate

Lemonade Change

House Robber

Find All Numbers Disappeared in an Array

Find All Duplicates in an Array

Same Tree

Design In-Memory File System

31.

Conclusion

1 Lessons

Where to Go from Here?

Coding Patterns

Mock Interview

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AI Code Mentor

AI Code Mentor helps you quickly identify errors in your code, learn from your mistakes, and nudge you in the right direction — just like a 1:1 tutor!

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