Problem Solving

A collection of data structures, algorithms, and competitive programming solutions in Python, Java, and Kotlin.

Table of Contents

• Project Structure
• Languages
• LeetCode Solutions
• Data Structures & Algorithms
• Practice Platforms
• Pandas Challenges
• Resources

Project Structure

.
├── ds_algo/               # Data structure & algorithm implementations
│   ├── dp/                # Dynamic Programming
│   ├── graph/             # Graph algorithms (BFS, etc.)
│   ├── greedy/            # Greedy algorithms
│   ├── linkedlist/        # Linked list implementations
│   ├── recursion/         # Recursion problems
│   ├── search/            # Search algorithms
│   ├── sorting/           # Sorting algorithms
│   └── tree/              # Binary tree implementations
├── LeetCode/              # LeetCode solutions (Python) - 200+ problems
│   ├── blind150/          # Blind 75/150 problems
│   └── 60 days challenge/ # 60-day challenge (14 days)
├── LeetCode-Java/         # LeetCode solutions (Java)
├── pandas/                # LeetCode Pandas challenges
└── problems/              # Problems from various platforms
    ├── algoe/             # AlgoExpert problems
    ├── course/            # Course-based problems
    ├── CrackingCodingInt/ # Cracking the Coding Interview
    ├── hacker_earth/      # HackerEarth solutions
    └── hacker_rank/       # HackerRank solutions

Languages

Language	File Count
Python	~350
Java	~53
Kotlin	1

LeetCode Solutions

200+ problems solved in Python, with select problems also solved in Java.

Categories

• Blind 75/150 — Curated list of frequently asked interview questions (LeetCode/blind150/)
• 60-Day Challenge — Structured daily challenge spanning 14 days (LeetCode/60 days challenge/)
• By Topic — Problems organized by number across arrays, trees, linked lists, graphs, DP, binary search, strings, and more

Java Solutions

13 problems solved in Java covering Two Sum, 3Sum, Container With Most Water, Valid Parentheses, Merge Two Sorted Lists, and others in LeetCode-Java/.

Data Structures & Algorithms

Implementations in Python under ds_algo/:

Category	Topics
Sorting	Bubble, Insertion, Selection, Merge, Quick, Counting
Graph	BFS, disconnected graph traversal
Dynamic Prog.	0/1 Knapsack (memoization & tabular), Fibonacci
Tree	Binary tree traversals and operations
Linked List	Single, double, circular linked lists
Greedy	Fractional Knapsack, minimum coins, N meetings
Search	Ternary search
Recursion	Sort array, reverse stack
Basic DS	Stack, Queue, Dequeue

Practice Platforms

HackerRank

Problems across Java intro, strings, data structures, and 30 Days of Code challenges.

HackerEarth

Solutions for basic I/O, math, operators, and implementation problems.

AlgoExpert

Easy-level problems including Two Number Sum, Valid Subsequence, Tournament Winner, Sorted Squared Array, and Non-Constructible Change.

Cracking the Coding Interview

Array and string problems including Is Unique.

Pandas Challenges

28 LeetCode Pandas problems solved using Python's pandas library in pandas/.

Resources

• LeetCode Problems Tracker (Google Sheet)