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Topics/Number Theory & Modular Arithmetic
intermediate level

Number Theory & Modular Arithmetic

Quick Answer

What is Number Theory & Modular Arithmetic?

Number theory problems appear in nearly every competitive programming contest. RunTimeFix covers the essential toolkit: divisibility rules, GCD and LCM computation, primality testing, the sieve of Eratosthenes, prime factorization, modular arithmetic (including modular inverse via Fermat's little theorem), binary exponentiation, and combinatorics (nCr mod p). These aren't abstract math topics — they're practical algorithms you'll use to solve real contest problems. Every concept is implemented in clean C++ with edge cases handled.

  • number theory
  • modular arithmetic
  • GCD
  • LCM
  • primes
  • sieve of Eratosthenes
  • binary exponentiation
  • combinatorics

Study Material for Number Theory & Modular Arithmetic

Ch 12: Basic Number Theory & Modular Arithmetic

Divisibility · GCD & LCM · Primes & Primality Testing · Sieve of Eratosthenes · Prime Factorization · Divisor Enumeration · Modular Arithmetic · Binary Exponentiation · Parity Arguments · Sum Formulas

Ch 29: Modular Inverse, Combinatorics & Fast Math

Modular Multiplicative Inverse · Combinatorics: C(N, K) mod M · Common Combinatorial Problems · Matrix Exponentiation (Fast Math)

Related Topics

AlgorithmsCompetitive ProgrammingC++ for Competitive Programming
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