🧠 DSA Mastery

A comprehensive C++ practice repository for Data Structures & Algorithms

Arrays · Linked Lists · Trees · Graphs · Sorting · Searching · Recursion · Dynamic Programming

---

✨ Topics Covered

📦 Data Structures Arrays & 2D Arrays Vectors & 2D Vectors Linked Lists (Single, Double, Circular) Stack & Queue (Circular, Deque) Binary Tree & BST Map & Set

⚙️ Algorithms Sorting (Bubble, Insertion, Selection, Merge, Quick, Cycle) Searching (Linear, Binary) Recursion (Basics & Intermediate) Bit Manipulation Prefix Sum & Sliding Window Pattern Problems

🧩 Problem Solving LeetCode problems (DSA Sheet) Product-based company questions Service-based company questions Mathematical problems String manipulation Pointer-based problems

---

📁 Project Structure

Click to expand / collapse the full directory tree

DSA/
├── CPP Basics/                          ← Foundational C++ programs
│   ├── PrintHello.cpp
│   ├── SumOf2Numbers.cpp
│   ├── SimpleInterest.cpp
│   ├── CircleArea.cpp
│   └── ...40+ files
│
├── Conditional/                         ← Decision-making constructs
│   ├── If Else/                         (21 problems)
│   │   ├── Calculator.cpp
│   │   ├── LeapYearOrNot.cpp
│   │   └── ...
│   ├── Switch/                          (16 problems)
│   │   ├── Calculator.cpp
│   │   └── ...
│   └── Ternary/                         (10 problems)
│       ├── GreatestAmong3.cpp
│       └── ...
│
├── Loop/                                ← Iteration constructs
│   ├── For Loop/                        (40+ problems)
│   │   ├── FibonacciSeries.cpp
│   │   ├── PrimeNumber.cpp
│   │   └── ...
│   ├── While Loop/                      (40+ problems)
│   │   └── ...
│   └── Do While Loop/                   (30+ problems)
│       └── ...
│
├── Functions/                           ← Function-based problems
│   ├── Factorial.cpp
│   ├── FindGCD.cpp
│   ├── PalindromeOrNot.cpp
│   └── ...50+ files
│
├── Pointers/                            ← Pointer concepts & usage
│   ├── PointerIntro.cpp
│   ├── DoublePointer.cpp
│   ├── PassByReference.cpp
│   ├── PassByValue.cpp
│   └── ...25+ files
│
├── Array/                               ← 1D Array operations
│   ├── MaximumElement.cpp
│   ├── SecondMaximumElement.cpp
│   ├── Subarray.cpp
│   └── ...40+ files
│
├── Vector/                              ← STL Vector operations
│   ├── VectorBasics.cpp
│   ├── Sort0And1And2ByThreePointer.cpp
│   ├── Merge2SortedArray.cpp
│   └── ...60+ files
│
├── 2D Arrays/                           ← Matrix operations
│   ├── TransposeOfMatrix.cpp
│   ├── Rotate90Degree.cpp
│   ├── SpiralModel.cpp
│   ├── MatrixMultiplication.cpp
│   └── ...25+ files
│
├── 2D Vectors/                          ← 2D Vector problems
│   ├── PascalTriangle.cpp
│   ├── SearchIn2DMatrix.cpp
│   ├── SpiralMatrix.cpp
│   └── ...16 files
│
├── String/                              ← String manipulation
│   ├── Introduction/                    (20+ basics)
│   │   ├── ReverseFromIndex2To5.cpp
│   │   └── ...
│   ├── BulitInFunction/                 (11 STL string functions)
│   │   ├── Reverse.cpp
│   │   ├── Sort.cpp
│   │   └── ...
│   └── Intermediate/                    (11 problems)
│       ├── LongestCommonPrefix.cpp
│       ├── ValidAnargam.cpp
│       └── ...
│
├── Sorting/                             ← Sorting algorithms
│   ├── Bubble Sort/                     (10 variants)
│   │   ├── IncreasingOrder.cpp
│   │   ├── OptimizedIncreasingOrder.cpp
│   │   └── ...
│   ├── Insertion Sort/                  (4 variants)
│   ├── Selection Sort/                  (2 variants)
│   └── Problems On Sorting/             (9 LeetCode problems)
│       ├── KthLargestElementFirstApproach.cpp
│       ├── MajorityElement.cpp
│       └── ...
│
├── Advance Sorting/                     ← Advanced sorting techniques
│   ├── Merge Sort/                      (5 problems)
│   │   ├── IncreasingOrderMergeSort.cpp
│   │   ├── CountInversionOptimized.cpp
│   │   └── ...
│   ├── Quick Sort/                      (3 variants)
│   │   ├── QuickSortByTakingStartEle.cpp
│   │   └── ...
│   └── Cycle Sort/                      (5 problems)
│       ├── MissingNumber.cpp
│       ├── FindTheDuplicateNumber.cpp
│       └── ...
│
├── Searching/                           ← Search algorithms
│   ├── Linear Search/                   (8 problems)
│   │   ├── FindTargetElement.cpp
│   │   ├── LowerBound.cpp
│   │   └── ...
│   └── Binary Search/                   (17 problems)
│       ├── FindLowerBound.cpp
│       ├── KokoEatingBananas.cpp
│       ├── CapacityToShipPackagesWithinDDays.cpp
│       └── ...
│
├── Recursion/                           ← Recursive problem solving
│   ├── Basics/                          (14 problems)
│   │   ├── CalculateFactorial.cpp
│   │   ├── TowerOfHanoi.cpp
│   │   └── ...
│   └── Intermediate/                    (45+ problems)
│       ├── GenerateParentheses.cpp
│       ├── PermutationSequence.cpp
│       ├── MazePath.cpp
│       └── ...
│
├── Diveinto Mathematics/                ← Math-based algorithms
│   ├── Bitwise Operator/                (12 problems)
│   │   ├── NumberOfSetBits.cpp
│   │   ├── Find2UniqueElement.cpp
│   │   └── ...
│   ├── Prefix Sum/                      (18 problems)
│   │   ├── PrefixSum.cpp
│   │   ├── ProductOfArrayItself_Method1.cpp
│   │   └── ...
│   └── Sliding Window/                  (10 problems)
│       ├── MaximumSumOfSubarraySizeK.cpp
│       ├── MinimumSizeSubarraySum.cpp
│       └── ...
│
├── Bits Manipulation/                   ← Bit-level operations
│   ├── PowerOf2.cpp
│   ├── PowerOf4.cpp
│   └── PartyOfCouples.cpp
│
├── Maths/                               ← Mathematical problems
│   ├── CountPrimes.cpp
│   ├── PerfectNumber.cpp
│   ├── UglyNumber.cpp
│   └── ...8 files
│
├── Pattern Problems/                    ← Pattern printing
│   ├── Star Pattern/                    (13 patterns)
│   │   ├── Pyramid.cpp
│   │   ├── HollowPyramid.cpp
│   │   └── ...
│   ├── Numerical Pattern/               (17 patterns)
│   │   ├── NumberPattern1.cpp
│   │   └── ...
│   ├── Alphabet Pattern/
│   │   ├── Capital Letter/              (20 patterns)
│   │   └── Small Letter/               (15 patterns)
│   └── Complex Pattern/                 (10 patterns)
│       ├── DiamondStar.cpp
│       ├── ArrowShaped.cpp
│       └── ...
│
├── Single Linked List/                  ← Singly linked list
│   ├── InsertInLinkedList.cpp
│   ├── ReverseLinkedList.cpp
│   ├── LinkedListCycle.cpp
│   ├── Merge_K_SortedList.cpp
│   └── ...50+ files
│
├── Double Linked List/                  ← Doubly linked list
│   ├── AddElementsAtHead.cpp
│   ├── ReverseDoubleLinkedList.cpp
│   └── ...22 files
│
├── Circular Linked List/
│   └── Circular Single Linked List/     (15 files)
│       ├── All_InsertionOperation.cpp
│       └── ...
│
├── Stack/                               ← Stack data structure
│   ├── ImplementStackByArray.cpp
│   ├── ImplementingStackUsingLinkedList.cpp
│   ├── InfixToPostfixExpression.cpp
│   ├── LargestRectangleInHistogram.cpp
│   ├── MinStackWithMostOptimizedSolution.cpp
│   └── ...60+ files
│
├── Queue/                               ← Queue data structure
│   ├── ImplementQueueUsingArray.cpp
│   ├── ImplementUsingLinkedList.cpp
│   ├── PopEfficientImplementUsingStack.cpp
│   ├── RevealCardsInIncreasingOrder.cpp
│   └── ...35+ files
│
├── Circular Queue/
│   ├── DesignCircularQueue.cpp
│   └── CircularQueueImplementaionUsingVector.cpp
│
├── Dequeue/                             ← Double-ended queue
│   ├── DequeImplementation.cpp
│   ├── ImplementDequeUsingDoubleLinkedList.cpp
│   ├── SlidingWindowMaximum.cpp
│   └── ...14 files
│
├── Binary Tree/                         ← Binary tree problems
│   ├── Basics/                          (15 problems)
│   │   ├── DiameterOfBinaryTree.cpp
│   │   ├── LowestCommonAncesorOfBinaryTree.cpp
│   │   └── ...
│   ├── Traversals/                      (15 traversal methods)
│   │   ├── BFS.cpp
│   │   ├── BinaryTreeLevelOrderTraversal.cpp
│   │   └── ...
│   └── InterView Question/              (13 problems)
│       ├── BinaryTreeLeftSideView.cpp
│       ├── BoundaryTraversal.cpp
│       └── ...
│
├── Binary Search Tree/                  ← BST problems
│   ├── Basics/                          (8 problems)
│   │   ├── InsertIntoBinarySearchTree.cpp
│   │   ├── ValidateBinarySearchTree.cpp
│   │   └── ...
│   ├── Deletion/                        (9 problems)
│   │   ├── DeleteNodeInBST.cpp
│   │   └── ...
│   └── Moris Traversal/                 (3 problems)
│       ├── MorisTraversal.cpp
│       └── FlattenBinaryTreeToLinkedList.cpp
│
├── Map/
│   └── Basic/                           (6 operations)
│       ├── InsertionType1.cpp
│       ├── DeleteInMap.cpp
│       └── ...
│
├── Set/
│   ├── Basic/                           (6 operations)
│   │   ├── InsertionInSet.cpp
│   │   └── ...
│   └── Leetcode/                        (2 problems)
│
└── DSA Sheet/                           ← Curated interview problems
    ├── Product Based/
    │   ├── Array & Numbers/
    │   │   └── majorityElement.cpp
    │   └── String/
    │       └── lengthOfLastWord.cpp
    └── Service Based/
        ├── Array & Numbers/
        │   ├── containsDuplicate.cpp
        │   └── majorityElement.cpp
        ├── Stack & Queue/
        │   └── minStack.cpp
        ├── String/
        │   └── lengthOfLastWord.cpp
        └── Two Pointer & Sliding Window/

---

🚀 Getting Started

Prerequisites

Compile & Run

# Compile a single file
g++ -std=c++17 -o output filename.cpp

# Run
./output

# Compile with warnings (recommended)
g++ -std=c++17 -Wall -Wextra -o output filename.cpp

Example

cd "Sorting/Merge Sort"
g++ -std=c++17 -o mergesort IncreasingOrderMergeSort.cpp
./mergesort

---

🧰 Topic Quick Reference

Topic	Folder	Problems
C++ Basics	CPP Basics/	40+
Conditionals	Conditional/	47
Loops	Loop/	110+
Functions	Functions/	50+
Pointers	Pointers/	25+
Arrays	Array/	40+
Vectors	Vector/	60+
2D Arrays	2D Arrays/	25+
Strings	String/	42+
Sorting	Sorting/ + Advance Sorting/	30+
Searching	Searching/	25
Recursion	Recursion/	60+
Linked Lists	Single/Double/Circular Linked List/	90+
Stack	Stack/	60+
Queue	Queue/ + Circular Queue/ + Dequeue/	50+
Trees	Binary Tree/ + Binary Search Tree/	43
Math	Maths/ + Diveinto Mathematics/	40+
Patterns	Pattern Problems/	75+
DSA Sheet	DSA Sheet/	Growing

---

🌍 Problem Sources

🟡 LeetCode	📘 Custom	🏢 Product Based	🏗️ Service Based
Binary Search, Trees, DP	Sorting, Patterns, Basics	Arrays, Strings, Stack	Arrays, Strings, Two Pointer

---

🤝 Contributing

# 1. Clone the repo
git clone <repo-url>
cd DSA

# 2. Create a topic branch
git checkout -b topic/<topic-name>

# 3. Add your solution
# Follow naming convention: PascalCase.cpp

# 4. Commit with a clear message
git add .
git commit -m "feat(binary-search): add KthSmallestInMatrix"

# 5. Push and open a PR
git push origin topic/<topic-name>

Naming convention: PascalCase.cpp — e.g., FindTheDuplicateNumber.cpp

Rule	Requirement
✅ File naming	PascalCase.cpp
✅ Folder placement	Place in the correct topic folder
✅ Code style	Clean, readable, with comments where needed
✅ Compilation	Must compile with g++ -std=c++17

---

Made with ❤️ by Rahul Goswami