🚀 Competitive Programming & Algorithmic Problem Solving

A growing multi-platform problem-solving archive with 455+ LeetCode solves, 422 CodeChef solves, 306 Codeforces solves, reusable templates, and focused algorithm notes.

👤 Profiles • Codeforces • LeetCode • CSES • CodeChef • HackerEarth • HackerRank • GeeksforGeeks • AtCoder • Templates • Notes

---

📌 At a Glance

455 LeetCode solves

422 CodeChef solves

306 Codeforces problems

2,000 HackerEarth points

322 Repository C++ files

_{Profile statistics and repository metrics in this overview are kept aligned with the linked profiles and this codebase.}

---

👤 Competitive Programming Profiles & Standings

Platform	Profile Link	Handle / Username	Key Rating / Standing	Solved Count	Prestigious Badges & Honors
LeetCode	prathamkashyap	@prathamkashyap	1550 contest rating	455 solved	Rank 253,859 · 7 badges
Codeforces	prathamkashyap	@prathamkashyap	815 (Newbie)	306 unique solved	280 in last year · 100 last month
CodeChef	prathamkashyap	@prathamkashyap	922 overall · 1067 DSA	422 solved	3 contests · Diamond League Level 5
HackerEarth	prathamkashyap	@prathamkashyap	2,000 points	83 solved / 103 submitted	Top 1% Basic Programming
HackerRank	prathamkashyap	@prathamkashyap	Problem Solving badge	Recent accepted C++ submissions	C++, Java, Python, SQL badges
GeeksforGeeks	prathamkashyap	@prathamkashyap	New profile	Starting point	Ready for future practice

---

📊 Solved Problems Matrix

Platform	Solved / Activity	Progress Snapshot
LeetCode	455	160 Easy · 232 Medium · 63 Hard · Rating 1550
Codeforces	306	280 last year · 100 last month · 68-day max streak
CodeChef	422	Rating 922 · DSA 1067 · 3 contests · 66/100 days
HackerEarth	83	103 submissions · 2,000 points · Top 1% Basic Programming
HackerRank	Active	Problem Solving, C++, Java, Python, SQL badges
GeeksforGeeks	Starting point	Profile created; practice roadmap ready
Repository	322	C++ solutions currently checked into this repository

---

📂 Repository Structure

competitive-programming/
├── codeforces/          # 322 C++ solutions categorized by difficulty rating
│   ├── 800/             # Fundamental implementation & greedy (83 solutions)
│   ├── 900/              # 36 solutions
│   ├── 1000/             # 44 solutions
│   ├── 1100/             # 39 solutions
│   ├── 1200/             # 41 solutions
│   ├── 1300/             # 34 solutions
│   ├── 1400/             # 5 solutions
│   ├── 1500/             # 7 solutions
│   ├── 1600/             # 0 solutions
│   ├── 1700/, 1800/, 2000/ # 1 solution each
│   └── unrated_questions/ # 30 solutions
├── leetcode/            # LeetCode patterns and profile progress
├── cses/                # CSES roadmap and section tracking
├── atcoder/             # AtCoder roadmap and contest notes
├── codechef/            # CodeChef profile, ratings, and contest progress
├── hackerearth/         # Practice tracks and profile achievements
├── hackerrank/          # Skills, badges, and submission highlights
├── geeksforgeeks/       # GeeksforGeeks profile and practice roadmap
├── templates/           # Reusable CP boilerplate & data structure templates
│   ├── cpp/             # C++ Fast I/O, DSU, Segment Tree, Sieve, Fenwick Tree
│   ├── python/          # Python fast I/O & math utility templates
│   └── java/            # Java FastScanner & FastWriter templates
└── notes/               # Curated algorithmic notes, cheat sheets & complexity tables

---

⚡ Quick Start & Compilation

C++20 Standard Build Flag

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

Fast I/O Snippet

#include <iostream>
using namespace std;

void fast_io() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
}

---

🛠️ Reusable CP Templates

Located in /templates:

Template	Language	Complexity	Direct Link
Fast I/O & Universal CP Boilerplate	C++20	$O(1)$	template.cpp
Disjoint Set Union (DSU)	C++20	$O(\alpha(N)) \approx O(1)$	dsu.cpp
Segment Tree (Point Update, Range Query)	C++20	$O(\log N)$	segment_tree.cpp
Fenwick Tree (Binary Indexed Tree)	C++20	$O(\log N)$	fenwick_tree.cpp
Linear Sieve & Prime Factorization (SPF)	C++20	$O(N)$ build, $O(\log K)$ factor	sieve_prime.cpp
Modular Arithmetic & Combinations	C++20	$O(\log MOD)$ power / inverse	modular_arithmetic.cpp
BFS, Topological Sort & Dijkstra	C++20	$O(V + E)$ to $O((V+E)\log V)$	graph_traversal.cpp
Prefix & Difference Arrays	C++20	$O(1)$ query/update after $O(N)$ build	prefix_sums.cpp
Sliding Window & Prefix Frequency	C++20	$O(N)$ amortized	sliding_window.cpp
Python CP Template	Python 3	Optimized Fast I/O	template.py
Java CP Template	Java	Custom FastScanner & FastWriter	Template.java

---

📖 Theory & Cheat Sheets

Explore quick revision guides in /notes:

• ⏱️ Time Complexity & Resource Limits - Operations per second ($10^8$), integer boundaries, and memory limits.
• 🔢 Number Theory & Modular Arithmetic - Fermat's Little Theorem, modular inverse, and $nCr \pmod p$.
• 💻 Bit Manipulation Hacks - Bitmask operations, subset generation, and GCC builtins (__builtin_popcount, __builtin_clz).
• 🌲 Graph Theory & Tree Algorithms - BFS, DFS, Dijkstra, Bellman-Ford, Floyd-Warshall, Kruskal, and LCA.
• 💡 Dynamic Programming Patterns - 0/1 Knapsack, LIS ($O(N \log N)$), LCS, Grid DP, and Space Optimization.
• 🎯 Greedy & Binary Search Patterns - Exchange arguments, monotonic predicates, interval choices, and answer-space search.

---

🤝 Connect

• GitHub: @prathamkashyap
• LinkedIn: Pratham Kashyap
• LeetCode: prathamkashyap
• Codeforces: prathamkashyap
• CodeChef: prathamkashyap
• HackerEarth: prathamkashyap
• HackerRank: prathamkashyap
• GeeksforGeeks: prathamkashyap

_{Designed & Maintained with 💻 and ☕ by Pratham Kashyap.}