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Algorithms

DataStructures

Mathematics

Fundamentals
Number Theory
Combinatorics
Algebra
Geometry
Probability
Linear Algebra Foundations

Java

Introduction
Strings
BigNumber
Data Structures
Object Oriented Programming
Exception Handling
Advanced

Warmup

# Title Solution Time Space Difficulty Points Note

Solve Me First

Java
C#

O(1)

O(1) Easy 1

Simple Array Sum

Java
C#

O(n)

O(1) Easy 10

Compare the Triplets

Java
C#

O(1)

O(1) Easy 10

A Very Big Sum

Java
C#

O(n)

O(1) Easy 10

Diagonal Difference

O(n)

O(1) Easy 10

Plus Minus

O(n)

O(1) Easy 10

Staircase

O(n)

O(n) Easy 10

Mini-Max Sum

O(1)

O(1) Easy 10

Time Conversion

O(1)

O(1) Easy 15

Birthday Cake Candles

O(n)

O(1) Easy 10

Implementation

# Title Solution Time Space Difficulty Points Note

Grading Students

O(n)

O(1) Easy 10

Apple and Orange

O(n+m)

O(1) Easy 10

Kangaroo

Java
C#

O(1)

O(1) Easy 10

Between Two Sets

Java
C#

O(x(n+m))

O(1) Easy 10 x=(max(m) - min(n))/min(n)

Divisible Sum Pairs

O(n^2)

O(1) Easy 10

Birthday Chocolate

Java
C#

O(n)

O(1) Easy 10

Breaking the Records

Java
C#

O(n)

O(1) Easy 10

Migratory Birds

O(n)

O(1) Easy 10

Day of the Programmer

O(1)

O(1) Easy 15

Bon Appetit

O(n)

O(1) Easy 10

Sock Merchant

Java
C#

O(n)

O(n) Easy 10

Drawing Book

Java
C#

O(1)

O(1) Easy 10

Counting Valleys

O(n)

O(1) Easy 15

Cats and a Mouse

Java
C#

O(1)

O(1) Easy 15

Electronics Shop

O(n log (n))

O(1) Easy 15 n = m+n

Picking Numbers

Java
C#

O(n)

O(n) Easy 20

Climbing the Leaderboard

O(n+m)

(n) Easy 20

The Hurdle Race

Java
C#

O(n)

O(1) Easy 15

Designer PDF Viewer

O(n)

O(n) Easy 20

Forming a Magic Square

Java

O(1)

O(1) Easy 20

Utopian Tree

O(n)

O(1) Easy 20

Angry Professor

O(n)

O(1) Easy 20

Beautiful Days at the Movies

O(n)

O(1) Easy 15

Viral Advertising

O(n)

O(1) Easy 15

Save the Prisoner!

Java
C#

O(1)

O(1) Easy 15

Circular Array Rotation

Java
C#

O(n)

O(1) Easy 20

Sequence Equation

Java
C#

O(n)

O(n) Easy 20

Jumping on the Clouds: Revisited

Java
C#

O(n)

O(n) Easy 15

Find Digits

Java
C#

O(n)

O(1) Easy 25

Extra Long Factorials

Java
C#

O(n)

O(1) Medium 20

Append and Delete

Java

O(n)

O(1) Easy 20

Sherlock and Squares

Java

O(n)

O(1) Easy 20

Library Fine

Java
C#

O(1)

O(1) Easy 15

Cut the sticks

Java
C#

O(n log(n))

O(n) Easy 25

Non-Divisible Subset

Java

O(n)

O(n) Medium 20

Repeated String

Java
C#

O(n)

O(n) Easy 20

Jumping on the Clouds

O(n)

O(n) Easy 20

Equalize the Array

O(n)

O(n) Easy 20

Queen's Attack II

Java

O(k)

O(1) Medium 30

ACM ICPC Team

Java

O(n^3)

O(n) Easy 25

Taum and B'day

O(1)

O(1) Easy 25

Organizing Containers of Balls

Java

O(n^2)

O(n^2) Medium 30

Encryption

O(n)

O(1) Medium 30

Bigger is Greater

Java

O(n)

O(n) Medium 35

Modified Kaprekar Numbers

O(n)

O(1) Easy 30

Minimum Distances

O(n)

O(n) Easy 20

Beautiful Triplets

O(n)

O(n) Easy 20

Strings: Making Anagrams

Java

O(|a|+|b|)

O(1) Easy 30

The Time in Words

O(1)

O(1) Medium 25

Chocolate Feast

O(log(n))

O(1) Easy 25 Base of logarithmic time complexity is m

Service Lane

O(n)

O(n) Easy 20

Lisa's Workbook

O(n)

O(1) Easy 25

Flatland Space Stations

O(n)

O(n) Easy 25

Fair Rations

O(n)

O(1) Easy 25

Cavity Map

O(n^2)

O(n^2) Easy 30

Manasa and Stones

O(n)

O(1) Easy 30

The Grid Search

Java

O(n)

O(n) Medium 30 n = len(word)

Happy Ladybugs

Java

O(n)

O(n) Easy 30

Strange Counter

Java

O(n)

O(1) Easy 30 n = t

Absolute Permuation

Java

O(n)

O(n) Medium 40

The Bomberman Game

Java

O(n*m)

O(n*m) Medium 40

Ema's Supercomputer

Java

Medium 40

Larry's Array

Java

Medium 40

Almost Sorted

Java

Medium 50

Matrix Layer Rotation

Python3

O(n*m)

O(n*m) Hard 80

Consecutive 1s in Binary Numbers

Java

O(n)

O(1) Easy 30

Nested Logic

Java

O(1)

O(1) Easy 40

Bitwise AND

Java

O(1)

O(1) Easy 20

Strings

# Title Solution Time Space Difficulty Points Note

Super Reduced String

O(n)

O(n) Easy 10

camelCase

O(n)

O(1) Easy 15

Strong Password

O(n)

O(1) Easy 15

Two Characters

O(n)

O(n) Easy 15

Caesar Cipher

O(n)

O(n) Easy 15

Caesar Cipher: Encryption

Java

O(n)

O(n) Easy 40

Mars Exploration

O(n)

O(1) Easy 15

HackerRank in a String!

O(n)

O(1) Easy 20

Pangrams

O(n)

O(1) Easy 20

Weighted Uniform Strings

O(n)

O(n) Easy 20

Separate the Numbers

Java
C#

O(n)

O(n) Easy 20

Funny String

O(n)

O(n) Easy 25

Gemstones

O(n)

O(1) Easy 20

Alternating Characters

O(n)

O(1) Easy 20

Beautiful Binary String

Java

O(n)

O(1) Easy 20

The Love-Letter Mystery

Java

O(n)

O(1) Easy 20

Determining DNA Health

Java

Hard 50

Palindrome Index

Java

O(n)

O(1) Easy 25

Anagram

Java

O(n)

O(1) Easy 25

Making Anagrams

Java

O(n)

O(n) Easy 30

Game of Thrones - I

O(n)

O(1) Easy 30

Two Strings

O(|a| + |b|)

O(1) Easy 25 a and b are lengths of the input strings

String Construction

Java

O(n)

O(n) Easy 25

Sherlock and Valid String

Java

O(n)

O(n) Hard 100

Richie Rich

Java
Python3

O(n)

O(n) Medium 30

Sherlock and Anagrams

Java

Medium 50

Common Child

Java

Hard 60

Bear and Steady Gene

Java

Medium 50

Morgan and a String

Java

O((|a|+|b|)^2)

O(|a| + |b|) Expert 100

Count Strings

Java

Hard 80

String Function Calculation

Java

Advanced 80

Build a Palindrome

Java

Advanced 80

Build a String

Java

Hard 80

Gridland Provinces

Java

Hard 80

Ashton and String

Java

Advanced 100

String Similarity

Java

Expert 100

Super Functional Strings

Java

Advanced 80

Circular Palindromes

Java

Advanced 120

Similar Strings

Java

Advanced 85

Save Humanity

Java

Expert 100

Find Strings

Java

Expert 100

Palindromic Border

Java

Expert 100

Two Two

Java

Advanced 150

Two Strings Game

Java

Expert 100

Letter Islands

Java

Expert 100

Pseudo-Isomorphic Substrings

Java

Expert 100

How Many Substrings?

Java

Expert 100

Sorting

# Title Solution Time Space Difficulty Points Note

Intro to Tutorial Challenges

O(n)

O(1) Easy 30

Insertion Sort - Part 1

O(n)

O(1) Easy 30

Insertion Sort - Part 2

O(n^2)

O(1) Easy 30

Correctness and the Loop Invariant

O(n^2)

O(1) Easy 30

Running Time of Algorithms

O(n^2)

O(1) Easy 30

Quicksort 1 - Partition

O(n)

O(n) Easy 10

Quicksort 2 - Sorting

O(n^2)

O(n) Easy 30

Quicksort In-Place

Java

O(n^2)

O(log(n)) Medium 35

Running Time of Quicksort

Java

O(n log(n))

O(log(n)) Easy 35

Counting Sort 1

O(n+k)

O(k) Easy 30 value of k in this problem is 100

Counting Sort 2

O(n+k)

O(n+k) Easy 30 Value of k is 100 in this problem.

Counting Sort 3

Java

O(n+k)

O(k) Easy 30

The Full Counting Sort

O(n+k)

O(n+k) Medium 40

Closest Numbers

O(n log(n))

O(n) Easy 35

Find the Median

O(n log(n))

O(n) Easy 35

Insertion Sort Advanced Analysis

Java

Advanced 50

Fraudulent Activity Notifications

Java

O(n^2)

O(n) Medium 40

Lily's Homework

Java

O(n log(n))

O(n) Medium 40

Big Sorting

O(n log(n))

O(n) Easy 20

Search

# Title Solution Time Space Difficulty Points Note

Hackerland Radio Transmitters

O(n log(n))

O(n) Medium 25

Ice Cream Parlor

O(n)

O(n) Easy 30

Binary Search: Ice Cream Parlor

Java

O(n)

O(n) Easy 35

Gridland Metro

Java
C#

O(k)

O(k) Medium 25 k = number of tracks

Missing Numbers

Java
C++
C#

O(n)

O(n) Easy 45

Minimum Loss

Java

O(n log(n))

O(n) Medium 35

KnightL on a Chessboard

Java

Medium 35

Pairs

Java
C++
C#

O(n log(n))

O(n) Medium 50

Sherlock and Array

Java
C++
C#

O(n)

O(n) Easy 40

Maximum Subarray Sum

Java

Hard 65

Connected Cells in a grid

Java

Medium 50

Short Palindrome

Java

Medium 40

Maximizing Mission Points

Java

Hard 70

Count Luck

Java

Medium 50

Cut the Tree

Java

Medium 50

Making Candies

Java

Hard 45

Gena Playing Hanoi

Java

Medium 50

Beautiful Quadruples

Java

Medium 50

Bike Racers

Java

Hard 65

Task Scheduling

Java

Advanced 70

Similar Pair

Java

Advanced 70

Absolute Element Sums

Java

Hard 70

Sorted Subsegments

Java

Hard 80

Distant Pairs

Java

Expert 80

King Richard's Knights

Java

Hard 80

Graph Theory

# Title Solution Time Space Difficulty Points Note

Roads and Libraries

Java

Medium 30

Synchronous Shopping

Java

Medium 40

Crab Graphs

Java

Medium 50

Even Tree

Java

Medium 50

Snakes and Ladders: The Quickest Way Up

Java

Medium 50

Subset Component

Java

Hard 50

Journey to the Moon

Java
Python3

O(n + i)

O(n) Medium 50

Kruskal (MST): Really Special Subtree

Java

Hard 50

Minimum Penalty Path

Java

Medium 50

Demanding Money

Java

Hard 50

The Story of a Tree

Java

Medium 50

Breadth First Search: Shortest Reach

Java

Medium 55

The Value of Friendship

Java

Hard 55

Clique

Java

Medium 60

Dijkstra: Shortest Reach 2

Java

Hard 60

Prim's (MST) : Special Subtree

Java

Medium 60

Roads in Hackerland

Java

Medium 60

Toll Cost Digits

Java

Hard 60

Real Estate Broker

Java

Hard 60

Matrix

Java

Hard 70

Bead Ornaments

Java

Advanced 70

Rust & Murderer

Java

O(n+m)

O(n) Medium 70

Recording Episodes

Java

Hard 70

Kingdom Connectivity

Java

Hard 75

Journey Scheduling

Java

Hard 75

Floyd : City of Blinding Lights

Java

Hard 75

Find the Path

Java

Hard 75

Repair Roads

Java

Hard 80

Problem solving

Java

Hard 80

Computer Game

Java

Hard 80

Jack goes to Rapture

Java

Medium 80

Jim and his LAN Party

Java

Hard 80

Jeanie's Route

Java

Medium 80

Travel in HackerLand

Java

Hard 80

Jogging Cats

Java

Advanced 80

Tree Flow

Java

Hard 80

Tripartite Matching

Java

Hard 80

Jumping Rooks

Java

Advanced 80

Minimum MST Graph

Java

Expert 80

Coprime Paths

Java

Expert 80

DAG Queries

Java

Expert 80

Liars

Java

Advanced 85

ByteLandianTours

Java

Hard 90

Kth Ancestor

Java

Hard 90

Drive

Java

Expert 90

Road Network

Java

Expert 90

Savita And Friends

Java

Hard 90

Favorite sequence

Java

Advanced 95

Quadrant Queries

Java

Advanced 100

Going to the Office

Java

Expert 100

Ticket

Java

Expert 100

HackerX

Java

Hard 100

Hacker Country

Java

Hard 100

Travelling Salesman in a Grid

Java

Expert 100

Huarongdao

Java

Expert 100

Vertical Paths

Java

Expert 100

DFS Edges

Java

Expert 100

Tree Splitting

Java

Advanced 100

Definite Random Walks

Java

Expert 100

Diameter Minimization

Java

Expert 100

Training the army

Java

Hard 120

Alex vs Fedor

Java

Expert 150

Greedy

# Title Solution Time Space Difficulty Points Note

Minimum Absolute Difference in an Array

O(n log(n))

O(n) Easy 15

Chief Hopper

Java

O(n)

O(n) Hard 65

Mark and Toys

Java
JS

O(n log(n))

O(n) Easy 35

Marc's Cakewalk

O(n + k)

O(k) Easy 15

Grid Challenge

Java

O(n*(n log (n)))

O(n^2) Easy 20

Luck Balance

Java

O(n log(n))

O(1) Easy 20

Maximum Perimeter Triangle

Java

O(n log (n))

O(n) Easy 20

Permuting Two Arrays

Java
JS

O(n log (n))

O(n) Easy 40

Jim and the Orders

Java

O(n log (n))

O(n) Easy 40

Equal Stacks

Java

O(n)

O(n) Easy 25

Sherlock and The Beast

Java

O(n)

O(n) Easy 30

Priyanka and Toys

Java
JS

O(n log(n))

O(n) Easy 30

Largest Permutation

O(n)

O(n) Easy 30

Beautiful Pairs

Java

Easy 30

Yet Another Minimax Problem

Java

Medium 20

Flipping the Matrix

Java

O(n^2)

O(n^2) Medium 30

Roads and Libraries

Java

Medium 30

Greedy Florist

O(n log (n))

O(n) Medium 35

Mark and Toys

Java

O(n log(n))

O(n) Easy 35

Max Min

Java

O(n log(n))

O(1) Medium 35

Permuting Two Arrays

Java

Easy 40

Jim and the Orders

Java

Easy 40

Goodland Electricity

Java

Medium 40

Fun Game

Java

Medium 40

Reverse Shuffle Merge

Java

Advanced 50

Cutting Boards

Java

Hard 60

Algorithmic Crush

Java

Hard 60

Prim's (MST): Special Subtree

Java

Medium 60

Accessory Collection

Java

Hard 60

Chief Hopper

Java

O(n)

O(n) Hard 65

Sherlock and MiniMax

Java

Hard 70

Team Formation

Java

Advanced 70

Dynamic Programming

# Title Solution Time Space Difficulty Points Note

Equal

Java

Medium 30

Cut Tree

Java

Medium 40

Mr K marsh

Java

Medium 40

Sam and sub-strings

Java

Medium 40

Summing Pieces

Java

Medium 40

Short Palindrome

Java

Medium 40

Abbreviation

Java

Medium 40

Fair Cut

Java

Medium 40

Fibonacci Modified

Java

Medium 45

Lego Blocks

Java

Medium 50

Candies

Java

Medium 50

Stock Maximize

Java

Medium 50

Angry Childtren 2

Java

Hard 50

The Maximum Subarray

Java

Medium 50

Sherlock and Cost

Java

Medium 50

Xor and Sum

Java

Medium 50

Counting Special Sub-Cubes

Java

Medium 50

Two Robots

Java

Medium 50

Kingdom Division

Java

Medium 50

Prime XOR

Java

Medium 50

HackerRank City

Java

Medium 50

Nikita and the Game

Java

Medium 50

Prime Digit Sums

Java

Medium 50

Mandragora Forest

Java

Medium 50

LCS Returns

Java

Medium 50

Grid Walking

Java

Medium 55

Bricks Game

Java

Medium 55

The Longest Common Subsequence

Java

Medium 55

Substring Diff

Java

Medium 60

Brick Tiling

Java

Hard 60

Alien Languages

Java

Hard 60

The Longest Increasing Subsequence

Java

Advanced 60

The Coin Change Problem

Python3

O(N*M)

O(N) Hard 60

Knapsack

Java

Medium 60

Sherlock's Array Merging Algorithm

Java

Hard 60

New Year Game

Java

Medium 60

Shashank and the Palindromic Strings

Java

Advanced 60

Decibinary Numbers

Java

Hard 60

Choosing White Balls

Java

Hard 60

DP: Coin Change

Java

Hard 60

Clues on a Binary Path

Java

Hard 60

GCD Matrix

Java

Hard 60

Coin on the Table

Java

Medium 65

Interval Selection

Java

Medium 65

Red John is Back

Java

Medium 65

Play with words

Java

Medium 65

Queens on Board

Java

Hard 70

String Reduction

Java

Hard 70

Far Vertices

Java

Hard 70

The Indian Job

Java

Medium 70

Hexagonal Grid

Java

Hard 70

Longest Palindromic Subsequence

Java

Hard 70

Turn Off the Lights

Java

Hard 70

Tara's Beautiful Permutations

Java

Hard 70

Two Subarrays

Java

Expert 70

Mining

Java

Advanced 75

The Longest Common Subsequence (LCS)

Java

Hard 75

Points in a Plane

Java

Advanced 80

Fairy Chess

Java

Advanced 80

Billboards

Java

Advanced 80

Requirement

Java

Advanced 80

A Super Hero

Java

Hard 80

Covering the stains

Java

Hard 80

Superman Celebrates Diwali

Java

Hard 80

Wet Shark and Two Subsequences

Java

Medium 80

Zurikela's Graph

Java

Hard 80

New Year Present

Java

Hard 80

Suffix Rotation

Java

Expert 80

Black and White Tree

Java

Hard 80

Beautiful Strings

Java

Hard 80

Longest Mod Path

Java

Hard 80

Super Functional Strings

Java

Advanced 80

Kitty's Calculations on a Tree

Java

Advanced 80

Liars

Java

Advanced 85

Dorsey Thief

Java

Advanced 85

Swap Permutation

Java

Medium 85

Candles Counting

Java

Medium 85

Square Subsequences

Java

Hard 90

Hyper Strings

Java

Advanced 90

Unique Divide And Conquer

Java

Advanced 90

Super Kth LIS

Java

Advanced 90

Counting Road Networks

Java

Expert 90

Lucky Numbers

Java

Expert 100

Count Scorecards

Java

Expert 100

Unfair Game

Java

Advanced 100

Oil Well

Java

Hard 100

Modify The Sequence

Java

Advanced 100

Divisible Numbers

Java

Expert 100

Ones and Twos

Java

Hard 100

Extremum Permutations

Java

Medium 100

Tree Pruning

Java

Advanced 100

P-sequences

Java

Hard 100

Best spot

Java

Advanced 100

Find the Seed

Java

Advanced 100

The Blacklist

Java

Advanced 100

Police Operation

Java

Hard 100

Road Maintenance

Java

Hard 100

King and Four Sons

Java

Expert 100

Counting the Ways

Java

Expert 100

Hard Disk Drives

Java

Expert 100

Travel around the world

Java

Medium 120

Robot

Java

Advanced 120

Vim War

Java

Advanced 120

Dortmund Dilemma

Java

Advanced 150

Separate the chocolate

Java

Expert 250

Constructive Algorithms

# Title Solution Time Space Difficulty Points Note

Lena Sort

Java

Medium 30

Flipping the Matrix

Java

O(n^2)

O(n^2) Medium 30

Gaming Array

Java

Medium 35

New Year Chaos

Java

Medium 40

Bonetrousle

Java

Medium 50

Yet Another KMP Problem

Java

Hard 60

Beautiful 3 Set

Java

Hard 60

Inverse RMQ

Java

Hard 60

Two Subarrays

Java

Expert 70

Lovely Triplets

Java

Advanced 80

Array Construction

Java

Advanced 80

Bit Manipulation

# Title Solution Time Space Difficulty Points Note

Lonely Integer

Java

O(n)

O(1) Easy 20

Maximizing XOR

Java

Easy 30

Counter game

Java

Medium 30

Xor-sequence

Java

Medium 40

Sum vs XOR

Java

O(n log(n))

O(1) Easy 20

The Great XOR

Java

Medium 25

Flipping bits

Java

Easy 40

Yet Another Minimax Problem

Java

Medium 30

Sansa and XOR

Java

Medium 30

AND Product

Java

Medium 40

Xoring Ninja

Java

Hard 55

Cipher

Java

Medium 50

XOR Matrix

Java

Hard 50

What's Next?

Java

Medium 50

String Transmission

Java

Hard 60

A or B

Java

Medium 50

Manipulative Numbers

Java

Hard 55

Stone game

Java

Hard 70

2's complement

Java

Advanced 70

Changing Bits

Java

Advanced 70

XOR key

Java

Advanced 80

Maximizing the Function

Java

Hard 70

XOR Subsequences

Java

Advanced 80

Iterate It

Java

Expert 90

Hamming Distance

Java

Expert 150

Mixing proteins

Java

Hard 80

Recursion

# Title Solution Time Space Difficulty Points Note

The Power Sum

Java

Easy 20

Crossword Puzzle

Java

Medium 30

Recursive Digit Sum

Java

Medium 30

Simplified Chess Engine

Java

Medium 40

Password Cracker

Java

Medium 40

Artithmetic Expressions

Java

Hard 40

K Factorization

Java

Hard 50

Bowling Pins

Java

Advanced 60

Simplified Chess Engine II

Java

Hard 60

Repetitive K-Sums

Java

Advanced 150

Game Theory

# Title Solution Time Space Difficulty Points Note

Game of Stones

O(n)

O(1) Easy 15

Tower Breakers

Java

Easy 15

A Chessboard Game

Java

Easy 15

Introduction to Nim Game

Java

Easy 15

Misère Nim

Java

Easy 20

Nimble Game

Java

Easy 20

Alice and Bob's Silly Game

Java

Medium 30

Poker Nim

Java

Easy 20

Tower Breakers, Revisited!

Java

Medium 25

Tower Breakers, Again!

Java

Medium 30

Zero-Move Nim

Java

Medium 50

Chessboard Game, Again!

Java

Medium 30

Digits Square Board

Java

Medium 35

Fun Game

Java

Medium 40

Stone Division

Java

Hard 50

Chocolate in Box

Java

Medium 70

Kitty and Katty

Java

Medium 80

Powers Game

Java

Medium 50

Deforestation

Java

Medium 50

Bob and Ben

Java

Medium 50

Tower Breakers - The Final Battle

Java

Medium 50

Simple Game

Java

Hard 60

Permutation game

Java

Medium 70

Move the Coins

Java

Hard 60

Play on benders

Java

Medium 70

New Year Game

Java

Medium 60

Stone Piles

Java

Hard 80

Chocolate Game

Java

Hard 90

Manasa and Prime game

Java

Hard 90

Vertical Rooks

Java

Medium 90

A stones game

Java

Medium 90

Tastes Like Winning

Java

Expert 100

NP Complete

# Title Solution Time Space Difficulty Points Note

Walking the Approximate Longest Path

Java

Hard 70

Sam's Puzzle (Approximate)

Java

Advanced 85

Spies, Revised

Java

Expert 100

TBS Problem

Java

Expert 100

Object Oriented Programming

# Title Solution Time Space Difficulty Points Note

Class vs. Instance

Java

N/A

N/A Easy 30

Inheritance

Java

O(n)

O(1) Easy 30

Abstract Classes

Java

N/A

N/A Easy 30

Complex Numbers

Java

O(1)

O(1) Easy 30

Arrays

# Title Solution Time Space Difficulty Points Note

Arrays - DS

O(n)

O(n) Easy 10

2D Array - DS

O(1)

O(1) Easy 15

Sparse Arrays

O(n + q)

O(n + q) Medium 25 n = number of input strings, q = number of queries

Dynamic Array

O(q) O(n) Easy 15 q = Number of queries

Linked Lists

# Title Solution Time Space Difficulty Points Note

Print the Elements of a Linked List

O(n)

O(1) Easy 5

Reverse a Linked List

Java

O(n)

O(1) Easy 5

Compare Two Linked Lists

O(n)

O(1) Easy 5

Delete a node

O(n)

O(1) Easy 5

Trees

# Title Solution Time Space Difficulty Points Note

Tree: Preorder Traversal

O(n)

O(n) Easy 10

Swap Nodes [Algo]

O(n)

O(n) Medium 40

Balanced Trees

# Title Solution Time Space Difficulty Points Note

Self Balancing Tree

O(log(n))

O(n) Medium 50

Stacks

# Title Solution Time Space Difficulty Points Note

Maximum Element

Push-O(1), Delete - O(n), Print - O(1)

Push - O(1), Delete - O(1), Print - O(1) Easy 20

Balanced Brackets

Java

O(n)

O(n) Medium 25

Queues

# Title Solution Time Space Difficulty Points Note

Queue using Two Stacks

Enqueue - O(1), Dequeue - O(n), Print - O(n)

Enqueue - O(1), Dequeue - O(1), Print - O(1) Medium 30

Heap

# Title Solution Time Space Difficulty Points Note

QHEAP1

Insert - O(log(n)), Delete - O(n), Print - O(1)

Insert - O(1), Delete - O(1), Print - O(1) Easy 25

Disjoint Set

# Title Solution Time Space Difficulty Points Note

Spaceholder

O(1)

O(1) Easy 1

Multiple Choice

# Title Solution Time Space Difficulty Points Note

Data Structures MCQ 1

Language Independent

NA Hard 5

Data Structures MCQ 2

Language Independent

NA Hard 5

Data Structures MCQ 3

Language Independent

NA Hard 5

Trie

# Title Solution Time Space Difficulty Points Note

Contacts

Add - O(L), Find - O(L) Add - O(L), Find - O(1) Medium 40 L = Length of a contact name

Advanced

# Title Solution Time Space Difficulty Points Note

Spaceholder

O(1)

O(1) Easy 1

Fundamentals

# Title Solution Time Space Difficulty Points Note

Leonardo's Prime Factors

O(1)

O(1) Easy 10

GitHub - RyanFehr/HackerRank: HackerRank solutions in Java/JS/Python/C++/C#

README.md

Algorithms

DataStructures

Mathematics

Java

Warmup

Implementation

Strings

Sorting

Search

Graph Theory

Greedy

Dynamic Programming

Constructive Algorithms

Bit Manipulation

Recursion

Game Theory

NP Complete

Object Oriented Programming

Arrays

Linked Lists

Trees

Balanced Trees

Stacks

Queues

Heap

Disjoint Set

Multiple Choice

Trie

Advanced

Fundamentals

Recommend

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