Codeforces

Contest solutions, editorial notes, and algorithmic observations.

asmofficial172006 · Expert · 0 → 1877 in 5 rated contests

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Overview

Solutions with editorial-style notes — key observations, invariants, failed approaches, and complexity analysis. The goal is to document how problems are solved, not just that they were solved.

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Contest Log

#	Contest	Div	Rank	Solved	Δ Rating
5	Codeforces Round 1101 (Div. 2)	2	510	5/6	1658 → 1803
4	Spectral Cup 2026 Round 2 (Codeforces Round 1100, Div. 1 + Div. 2)	1+2	1838	5/10	1549 → 1658
3	Codeforces Round 1099 (Div. 2)	2	152	5/6	1154 → 1549
2	Educational Codeforces Round 190 (Div. 2)	2	247	5/6	661 → 1154
1	Codeforces Round 1098 (Div. 2)	2	504	5/8	0 → 661

Each contest directory contains solutions and a README.md with per-problem editorial notes.

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Repository Structure

CodeForces/
│
├── README.md
│
├── contests/
│   ├── Codeforces Round 1098 (Div. 2)/
│   │   ├── README.md                  # per-problem editorial notes
│   │   ├── A.cpp                      # Marisa Steals Reimu's Takeout
│   │   ├── B.cpp                      # Remilia Plays Soku
│   │   ├── C1.cpp                     # Cirno and Number (Easy)
│   │   ├── C2.cpp                     # Cirno and Number (Hard)
│   │   └── D.cpp                      # Sanae, Cross and Color
│   │
│   ├── Educational Codeforces Round 190 (Div. 2)/
│   │   ├── README.md
│   │   └── A.cpp  B.cpp  C.cpp  D.cpp  E.cpp
│   │
│   ├── Codeforces Round 1099 (Div. 2)/
│   │   ├── README.md
│   │   └── A.cpp  B.cpp  C.cpp  D.cpp  E.cpp
│   │
│   ├── Spectral Cup 2026 Round 2 (Codeforces Round 1100, Div. 1 + Div. 2)/
│   │   ├── README.md
│   │   └── A.cpp  B.cpp  C1.cpp  C2.cpp  D.cpp
│   │
│   └── Codeforces Round 1101 (Div. 2)/
│       ├── README.md
│       └── A.cpp  B.cpp  C1.cpp  C2.cpp  D.cpp
│
├── topics/
│   └── INDEX.md                       # problems indexed by topic
│
└── notes/
    └── approach-patterns.md           # recurring observations and techniques

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Topic Index

Problems grouped by primary technique. See topics/INDEX.md for the full cross-referenced index.

Topic	Problems
Greedy	R1098-A, R1098-B, Edu190-A, R1100-A, R1100-B, R1100-C1, R1101-A
Prefix / Suffix	R1098-D, R1099-B, Edu190-B, R1100-C2, R1101-B
Binary Search	R1098-D, Edu190-E, R1100-D, R1101-C2
Constructive	R1099-A, R1099-D, R1100-C1, R1100-C2
Digit Construction	R1098-C1, R1098-C2
Dynamic Programming	R1101-C1
Tree DP	R1099-E
Sparse Table / RMQ	Edu190-E
Convergence / Simulation	R1099-C
Sweep / Events	Edu190-D, R1101-B
Divide and Conquer	R1101-D

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Profiles

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Feel free to explore the solutions and learn from them.
_{Aakash Mahori · College of Technology, Pantnagar · C++20 · G++ · VS Code}