Codeforces CP 31 — Solutions and Practice

This repository collects solutions for the "CP 31" Codeforces practice sheet (problems grouped by difficulty/ratings and contest practice). It is organized to make it easy to find, compile, and run individual problem solutions.

Repository structure

• 1000/, 1100/, 1200/, 800/, 900/, ... — folders named by common Codeforces rating tiers. Each folder contains solution source files for problems at that rating (for example 01_swap_and_delete.cpp).
• contests/ — space for full contest solutions or multi-file contest projects.
• README.md — this file.

Each solution file follows a simple naming convention:

• NN_description.cpp or NN_description.ext where NN is a two-digit index and description is a short snake_case title for the problem.

Examples from this repo:

• 1000/01_swap_and_delete.cpp — solution for the first problem in the 1000-rating group.
• 1200/05_vika_and_the_bridge.cpp

Build and run

Most solutions are standalone C++ source files. Two convenient ways to compile and run a solution are shown below.

1. Using g++ directly (macOS, Linux):

• Compile a file: g++ -std=c++17 -O2 -Wall -o solution source.cpp
• Run (optionally using redirected input): ./solution < input.txt > output.txt

2. Using the provided VS Code tasks

This workspace includes tasks you can run from VS Code:

• "compile" — compiles the current open file using g++.
• "compile and run" — compiles the current open file and runs it, redirecting stdin from input.txt and writing output to output.txt.

Run tasks from the Command Palette (Tasks: Run Task) or the Run/Build menu.

Testing

• For interactive testing, create an input.txt file next to a solution and run the "compile and run" task.
• Use small custom tests and compare output with expected results.