Concepts4

Modular Arithmetic Pitfalls

Modular arithmetic is about working with remainders, but programming languages often return negative remainders, so always normalize with (a % MOD + MOD) % MOD.

#modular arithmetic#modular inverse#fermats little theorem+12

⚙️AlgorithmIntermediate

Debugging Strategies for CP

Systematic debugging beats guesswork: always re-read the statement, re-check constraints, and verify the output format before touching code.

#competitive programming#debugging#stress testing+12

∑MathIntermediate

Chinese Remainder Theorem

The Chinese Remainder Theorem (CRT) reconstructs an integer from its remainders modulo pairwise coprime moduli and guarantees a unique answer modulo the product.

#chinese remainder theorem#crt#modular arithmetic+12

∑MathIntermediate

GCD and Euclidean Algorithm

The greatest common divisor (gcd) of two integers is the largest integer that divides both without a remainder.

#gcd#euclidean algorithm#extended euclidean+12