Erastosfen Sieve
unknown
c_cpp
3 years ago
410 B
5
Indexable
Never
class EratosfenSieve { public: vector<int> used; vector<int> pr; int N; EratosfenSieve(int N){ this->N = N; used.resize(N + 1); } void sieve() { pr.reserve(N / 10); for (long long i = 2; i <= N; i++) { if (!used[i]) { pr.push_back(i); for (long long j = i * i; j <= N; j += i) used[j] = true; } } } };