Competitive Programming & Algorithmic Problem Solving

A repository of algorithmic problem solutions, reusable templates, and algorithmic notes for competitive programming and interview preparation.

What This Repository Contains

• 400+ Codeforces solutions organized by difficulty rating (800-2000)
• Reusable C++ templates for common data structures and algorithms
• Algorithmic notes covering complexity, number theory, graphs, DP, and more
• Multi-language support with C++ as the primary language (Python and Java also available)

Quick Navigation

• Codeforces Solutions - Problems organized by rating
• Templates - Reusable boilerplate and data structures
• Notes - Algorithmic theory and cheat sheets
• Generated Statistics - Exact file counts and breakdowns
• Problem Index - Complete solution index

Repository Structure

competitive-programming/
├── codeforces/          # C++ solutions by difficulty rating
│   ├── 800/             # Fundamental problems
│   ├── 900/             # Easy problems
│   ├── 1000-2000/       # Intermediate to advanced
│   └── unrated_questions/
├── templates/           # Reusable templates
│   ├── cpp/             # C++ data structures
│   ├── python/          # Python utilities
│   └── java/            # Java fast I/O
├── notes/               # Algorithmic reference
├── docs/                # Documentation
│   └── generated/       # Auto-generated statistics
└── scripts/             # Repository automation

Compilation

C++20 Build

g++ -std=c++20 -O2 -Wall -Wextra solution.cpp -o solution
./solution < input.txt

Fast I/O

#include <iostream>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    // solve problem
}

Templates

The repository includes tested templates for:

• Fast I/O - Optimized input/output for competitive programming
• Disjoint Set Union (DSU) - $O(\alpha(N))$ union-find with path compression
• Segment Tree - Point update, range query in $O(\log N)$
• Fenwick Tree - Binary indexed tree for prefix sums
• Linear Sieve - $O(N)$ prime sieve with smallest prime factor
• Modular Arithmetic - Fast exponentiation, modular inverse, combinations
• Graph Traversal - BFS, topological sort, Dijkstra
• Prefix Sums - Range sum queries and difference arrays
• Sliding Window - At-most-K distinct, bounded sums

See templates/ for complete implementations.

Notes

Algorithmic reference material:

• Time Complexity & Limits - Operations per second, integer boundaries
• Number Theory - Modular arithmetic, GCD, sieve
• Bit Manipulation - Bitmask operations, GCC builtins
• Graphs & Trees - BFS, DFS, shortest paths, MST
• Dynamic Programming - Knapsack, LIS, LCS, patterns
• Greedy & Search - Exchange arguments, binary search

Generated Statistics

Repository Statistics

Exact repository statistics are generated automatically from the filesystem:

• Total code files: 403
• Languages: C++ (399), Python (2), Java (2)
• Codeforces solutions: 392
• Templates: 11

See docs/generated/stats.md for complete breakdowns and docs/generated/problem-index.md for the full problem index.

External Platform Statistics

Public profile statistics from external competitive programming platforms (verified from public APIs, GraphQL, and structured profiles):

Platform	Profile	Status	Solves / Rating	Key Highlights
LeetCode	@prathamkashyap	📸 snapshot	522 solved (171 E / 279 M / 72 H)	87.8% AC
Codeforces	@prathamkashyap	🟢 live	Rating 815 (newbie), 376 solved	Max rating 815, Official API verified
CodeChef	@prathamkashyap	🟢 live	Rating 922 (★ 1 Star), 631 solved	Diamond League, DSA Monday 1067 (Rank #2,341)
HackerRank	@prathamkashyap	🟢 live	26 stars, 356 solved	Problem Solving 6★ (#1,871), SQL 5★ (#1), C++ 5★/Java 5★/Python 5★
HackerEarth	@prathamkashyap	🟢 live	4,370 pts, 178 solved (217 subs)	14 badges
GeeksforGeeks	@prathamkashyap	📸 snapshot	Score 424, 98 solved	28 POTDs solved, 28d streak, 96 subs (2026)

Detailed Platform Breakdown & Honors

LeetCode (@prathamkashyap)

• Problem Solves: 522 total (🟢 Easy: 171, 🟡 Medium: 279, 🔴 Hard: 72)
• Submissions & Acceptance: 858 submissions, — accepted (87.8% AC rate)

Codeforces (@prathamkashyap)

• Current Rating: 815 (newbie) | Max Rating: 815 (newbie)
• Unique Solved Problems: 376

CodeChef (@prathamkashyap)

• Rating: 922 (★ 1 Star) | Max Rating: 922 | League: Diamond League
• DSA Monday Rating: 1067 (Rank #2,341) | Global Rank: #17,165
• Total Problems Solved: 631

HackerRank (@prathamkashyap)

• Skill Badges: Problem Solving (6★, #1,871), C++ (5★, #65,859), Java (5★, #231,773), Python (5★, #351,747), Sql (5★, #1)
• Total Stars & Solves: 26 stars earned, 356 challenges solved
• Verified Skills: Algorithm, Javascript(Intermediate), Data Structure, Python(Advanced), React, Css, NodeJs, SQL

HackerEarth (@prathamkashyap)

• Points & Solves: 4,370 points, 178 solved, 217 solutions submitted
• Badges: Data Structures - 1 Star, Data Structures - 2 Stars, Algorithms - 1 Star, Algorithms - 2 Stars, Basic Programming - 1 Star, Basic Programming - 2 Stars, Basic Programming - 3 Stars, Basic Programming - 4 Stars, Basic Programming - 5 Stars, Novice, Amateur, Explorer, Elite, C++ language

GeeksforGeeks (@prathamkashyap)

• Coding Score: 424 | Total Solved: 98
• Streaks & POTD: 28 POTDs solved, 28 day longest streak
• 2026 Activity: 96 submissions

See docs/generated/external-stats.md for complete external platform statistics with retrieved metrics, retrieval methods, and timestamps.

Note

External platform statistics represent actual progress on external accounts and are tracked independently from the solution files stored in this repository. Solved counts are maintained separately and not combined into a misleading total.

Automation

The repository includes:

• Statistics generation - scripts/generate_stats.py scans the repository and generates counts
• C++ validation - scripts/validate_cpp.py verifies compilation of all C++ files
• CI workflow - GitHub Actions validates compilation on push/PR

See scripts/ and .github/workflows/ for details.

Connect

• GitHub
• LinkedIn
• Codeforces