Combinatorics

Combinatorics

Practice problems, Problem Set, Combinatorics, Questions, Answers, Problems, Solutions, Discussions, Walkthroughs, Hints, IOQM, RMO, INMO, Study material, Olympiad Combinatorics Notes, Olympiad Combinatorics Problems
Lecture notes on Combinatorics (for Math Olympiad — IOQM, RMO, INMO)

Click on the links below to download.

Combinatorics  
Warm up
Coloring proofs
Auxiliary configuration
Induction
Inclusion-exclusion principle
Invariance principle
Pigeonhole principle
Extremal principle
Arrange in order
Grouping in pairs
Counting
Counting via bijections
Counting the complement
Counting in two different ways
Generating functions
  • Click here to download Algebra notes.
  • Click here to download Geometry notes.
  • Click here to download Number Theory notes.
  • Click here to download notes of INMO Training Camp 2025 for the Madhya Pradesh region.
  • Click here to download some problem set of IMO Training Camp 2025.

These notes

  • may be useful
    • to the students who would like to have a look at some of the past RMO problems, in order to have an idea of the notions/topics involved, and/or to have a glimpse before getting started, or just curious about it,
    • to the students, who would like to prepare and would like to have the relevant questions organized across the topics and sub-topics,
  • also aim

Problem sets by Amit Kumar Mallik from INMOTC 2025, MP region

Problem sets by Amit Kumar Mallik from INMOTC 2025, MP region  
Invariants and Monoinvariants
Coloring problems
Games
Optimization problems

References/Resources