🧠 Algorithms and Data Structures in Java This repository contains a comprehensive collection of algorithm and data structure
implementations in Java.
Java 11 or higher
Maven 3.6+
IDE (IntelliJ IDEA, Eclipse, VS Code)
git clone https://github.com/Daruuu/AlgoDS-Java.git
cd AlgoDS-Java
mvn clean compile Running Specific Examples mvn exec:java -Dexec.mainClass=" com.daruuu.Main"
Platform
Category
Solved
Status
LeetCode
Easy Arrays
16
✅
LeetCode
Easy Strings
6
✅
LeetCode
Easy Math
2
✅
LeetCode
Easy Two Pointers
8
✅
LeetCode
Medium Arrays
1
🔄
LeetCode
Medium Dynamic Programming
2
🔄
LeetCode
Medium Greedy
2
🔄
LeetCode
Medium Sorting
1
🔄
HackerRank
Algorithms
4
✅
HackerRank
Data Structures
1
🔄
Total All 41+ 🔄
📊 Big O Notation, Time & Space Complexity This section contains comprehensive notes and Java examples on how to analyze time and space complexity of algorithms.
View Big O Notation Guide Java Interview Questions
Data Structures Guide
⚡ Algorithm Complexity Reference
Algorithm
Time Complexity
Space Complexity
Best Case
Worst Case
Linear Search
O(n)
O(1)
O(1)
O(n)
Binary Search
O(log n)
O(1)
O(1)
O(log n)
Bubble Sort
O(n²)
O(1)
O(n)
O(n²)
Selection Sort
O(n²)
O(1)
O(n²)
O(n²)
Insertion Sort
O(n²)
O(1)
O(n)
O(n²)
Merge Sort
O(n log n)
O(n)
O(n log n)
O(n log n)
Two Sum (HashMap)
O(n)
O(n)
O(n)
O(n)
Two Pointers
O(n)
O(1)
O(1)
O(n)
Dynamic Programming
O(n) to O(n²)
O(n) to O(n²)
Varies
Varies
🏗️ New Organized Structure src/main/java/com/daruuu/
├── algorithms/ # Fundamental algorithms
│ ├── sorting/ # Sorting algorithms
│ └── searching/ # Searching algorithms
├── problems/ # Problems by platform
│ ├── leetcode/ # LeetCode problems
│ │ ├── easy/ # Easy problems by category
│ │ ├── medium/ # Medium problems by category
│ │ └── hard/ # Hard problems by category
│ └── hackerrank/ # HackerRank problems
│ ├── algorithms/ # Algorithm challenges
│ └── dataStructures/ # Data structure challenges
├── utils/ # Common utilities
├── complexity/ # Complexity analysis exercises
└── docs/ # Documentation
Algorithm
Description
Time Complexity
BubbleSortRepeatedly swaps adjacent elements in wrong order
O(n²)
SelectionSortSelects minimum element and places at correct position
O(n²)
InsertionSortBuilds sorted array by inserting one element at a time
O(n²)
MergeSortDivides array and merges sorted halves
O(n log n)
Algorithm
Description
Time Complexity
LinearSearchIterates through array to find target
O(n)
BinarySearchEfficiently searches sorted arrays using divide and conquer
O(log n)
problems/leetcode/easy/arrays/ (16 problems)problems/leetcode/easy/strings/ (6 problems)problems/leetcode/easy/math/ (2 problems)problems/leetcode/easy/twoPointers/ (8 problems)Medium Problems (6 total)problems/leetcode/medium/arrays/ (1 problem)problems/leetcode/medium/dynamicProgramming/ (2 problems)problems/leetcode/medium/greedy/ (2 problems)problems/leetcode/medium/sorting/ (1 problem)problems/hackerrank/algorithms/ (4 problems)
Algorithm
Description
AVeryBigSumSums large integers that may exceed standard data types
CompareTripletsCompares scores of two players based on multiple criteria
DiagonalDifferenceCalculates absolute difference between diagonals of square matrix
MiniMaxSumFinds minimum and maximum sum of 4 out of 5 integers
problems/hackerrank/dataStructures/ (1 problem)
Algorithm
Description
ReverseArrayReverses an array in-place using two pointers technique
Utility
Description
ListNodeCommon ListNode class for linked list problems
Exercise
Description
Exercise01.java to Exercise04.javaSimple Java programs designed to analyze and reason about algorithm complexity
File
Description
algorithms/README.mdSorting and searching algorithms guide
leetcode/README.mdLeetCode problems documentation
leetcode/TimeAndSpaceComplexOfAlgorithms.mdComplexity analysis notes
theory/big-o-notation.mdComplete Big O notation guide with examples
theory/java-interview-questions.mdCommon Java interview questions and answers
theory/data-structures-guide.mdComprehensive data structures guide
✅ Unit Testing with JUnit 5 Tests are located in the src/test/java/... directory, organized to mirror the
structure of your main code.
Written using JUnit 5
Each class has its corresponding test class
Assertions for correctness and edge cases
Fork el proyecto
Crea una rama para tu feature (git checkout -b feature/AmazingAlgorithm)
Commit tus cambios (git commit -m 'Add some AmazingAlgorithm')
Push a la rama (git push origin feature/AmazingAlgorithm)
Abre un Pull Request
Sigue las convenciones de Java
Incluye tests para nuevos algoritmos
Documenta la complejidad temporal y espacial
Actualiza el README si es necesario
Short Term (Next 2 weeks)
"Cracking the Coding Interview" by Gayle McDowell
"Introduction to Algorithms" by Cormen, Leiserson, Rivest, Stein
This project is licensed under the MIT License - see the LICENSE file for details.
Daruuu - GitHub
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HackerRank for algorithm challenges
All contributors who help improve this repository
