diff --git a/math/primes_up_to_10^8.cpp b/math/primes_up_to_10^8.cpp new file mode 100644 index 000000000..db9b56cab --- /dev/null +++ b/math/primes_up_to_10^8.cpp @@ -0,0 +1,27 @@ +#include +#include + +char prime[100000000]; + +void Sieve(int64_t n) { + memset(prime, '1', sizeof(prime)); // intitize '1' to every index + prime[0] = '0'; // 0 is not prime + prime[1] = '0'; // 1 is not prime + for (int p = 2; p * p <= n; p++) { + if (prime[p] == '1') { + for (int i = p * p; i <= n; i += p) + prime[i] = '0'; // set all multiples of p to false + } + } +} + + +int main() { + Sieve(100000000); + int64_t n; + std::cin >> n; // 10006187 + if (prime[n] == '1') + std::cout << "YES\n"; + else + std::cout << "NO\n"; +}