Learning Module for Beginners

Hi fellow programmers,

We are planning to create a course for beginners. Beginners often come to the site and got overwhelmed by so many problems present on the site. Many of them often ask where to start from. So, we thought of creating a course module for them. The module will be a set of tutorials and a set of practice contests on CodeChef.

For this module, we will identify the key set of topics that a beginner should solve in order to reach a certain level. For each topic, we will have some 5 to 10 or more problems on that topic that she should solve. I have collected some set of problems for following topics (in increasing order of the difficulty). Please feel free to give any relevant feedback, suggest some problems that you think can be added or removed. Any suggestions regarding would be most welcome.

Note that currently, this module is not ready. It’s still work in progress. I have marked this post a community wiki. Please feel free to edit it.

Module #0: What’s competitive programming?

What’s competitive programming? (tell about major competitions, platforms etc.) (This section need help in expanding)

Getting started with CodeChef platform

Module #1: Learning A Programming Language

Check https://www.codechef.com/ioi/basics, the section “Language Constructs - C++ - 1” for basic knowledge of C++. If you want to learn basics of other languages like Java, Python, you can refer to (need to provide more links).

Just get it done :slight_smile: Starting questions to do

  • FLOW001 (add two numbers)
  • FLOW002 (find reminder of a number when divided by other number)
  • TEST (one of the starting problem to solve on CodeChef)
  • INTEST (for testing whether your input/output routines are fast enough)

Basic knowledge of if/else conditions

  • FLOW010 (basic knowledge of if/else conditions)
  • FLOW014 (another if/else knowledge question)
  • LADDU (very nice implementation problem to solve)

Dealing with numbers

  • FLOW002 (find remainder of a number a % b)
  • FLOW004 (find sum of first and last digit of a number)
  • FLOW006 (find sum of digits of a number)
  • FLOW007 (given a number, reverse it)
  • FCTRL (an interesting question, must solve)

Basic knowledge of arrays

Working with strings

  • NITIKA (reading strings, and string related formatting)
  • GOODBAD (ASCII characters, lower-case and uppercase characters)
  • FLOW015 (checks basic knowledge of strings and calendar)
  • FRGTNLNG (very nice question to test input processing skills)
  • LAPIN (check whether a string is a palindrome or not)
  • CSUB (good for understanding notion of substrings)

Handling floating point numbers

Off to recursion

Provide Few More Implementation Problems:

Space and time complexity of a program

Module #2: (Basic Mathematics)

Please see https://www.codechef.com/ioi/basics, Mathematics section for very basic mathematics.

Basic Number Theory:

Module #3: Sorting algorithms

Module #4: Greedy Algorithms

Module #5: Stacks and Queues



  • CHFQUEUE (very nice stack and queue related problem, must do)
  • COOK82C (easy-med level problem)

Module #6: Binary Search:

Module #7: Basic Dynamic Programming

  • ALTARAY (basic dp problem)
  • SUMTRI (very nice and basic dp problem)
  • DBOY (very nice dp problem, must do)
  • XORSUB (basic 2-D dp)
  • STRMRG (a variation of standard LCS (longest common subsequence) problem, must do problem)
  • GRID (simple 2-D dp, prefix/suffix sums over a 2-D matrix, must do)
  • STRSUB (dp with binary search)

Module #8: Basic Graph Theory

Depth first search

  • FROGV (can also be done without requiring dfs by making some simple observations, in fact, dfs is overkill for it)
  • FIRESC (must do dfs problem, can also be done using union-find algorithm)
  • CHFNFRN (check whether a graph is bipartite)
  • DIVIDE (binary search with bipartite checking type logic)
  • MCO16104 (consider the inverse graph)
  • AUEC (existence of euler circuit in a graph)

Breadth first search

Union Find

  • BIGOF01 (very basic problem on union find, must do)
  • COLGQU (slight harder version on union find)
  • CHFNFRN (check whether a graph is bipartite)
  • MTRWY (slight harder version on union find)
  • JABO
  • FILLMTR (very nice problem on union find, intermediate level, you may also check the video tutorials)
  • GALACTIK (a very nice union find problem)
  • PARITREE (intermediate level problem)
  • SETELE (much recommended problem)
  • MAGICSTR (recommended only for intermediate+ level)

Advanced features of languages

Check Language Constructs. It’s good to learn Standard Template Library (STL) - C++ 2 section in https://www.codechef.com/ioi/basics for reading.