Stage 1 of 10 · 8 lessons · ~3 weeks
C++ for contests
Set up a compiler and a template, learn the STL containers and algorithms contests use every day, and learn to read constraints so you know what complexity you can afford.
Start: Reading constraints and time limitsLessons· one lesson for each topic, in this order
- 1Reading constraints and time limitsLesson
- 2Compiler, editor and flagsLesson
- 3Your template and fast input and outputLesson
- 4Vectors, pairs and sortingLesson
- 5Sets, maps and priority queuesLesson
- 6STL algorithms you will use weeklyLesson
- 7Integer overflow and choosing typesLesson
- 8Hash maps and anti-hash testsLesson
Do this
- Install g++ and an editor, and compile a program with warnings and with sanitizers.
- Write your contest template and type it from memory three times.
- Solve the first 10 CSES Introductory Problems in C++.
- Make an account on Codeforces and on AtCoder.
- Solve 10 problems rated 800 on Codeforces, reading the constraints first each time.
- Keep every accepted solution in a Git repository, one folder per platform.
Start with· follow one of these
- CourseFreeLearnCpp.com
LearnCpp.com · Beginner
Free and thorough: read the chapters on vectors, references, lambdas and the standard library if C++ is new to you
- BookFreeCompetitive Programmer's Handbook
Antti Laaksonen · Beginner
Chapter 1 covers C++ for contests, input and output and working with numbers; Chapter 2 covers complexity
Practise
Keep handy
Also worth your time
A clear walk through time and space complexity, the language you need to read constraints
- USACO GuideGo deeper
The General section has practical pages on choosing a language, fast input and output and debugging
Before moving on: A compiler and editor set up with warnings and sanitizers, a template you can type from memory, and the first two CSES sections or 20 easy Codeforces problems solved in C++.
You do not need all of C++ for contests. Vectors, pairs, sort, set, map, priority_queue and a handful of algorithms cover most problems for a long time. Learn those properly, keep your template short, and spend the rest of your time solving problems.