Update primes.cpp

Changes

1 changed files (+4/-4)

• Math/primes.cpp
  • @@ -3,16 +3,16 @@ bitset<10000001> bs;
    vector<int> pr; void sieve(int size) { - sieve_size = size + 1; + sieve_size = size; bs.set(); bs[0] = bs[1] = 0; - for (ll i = 2; i < sieve_size; ++i) if (bs[i]) { - for (ll j = i * i; j < sieve_size; j += i) bs[j] = 0; + for (ll i = 2; i <= sieve_size; ++i) if (bs[i]) { + for (ll j = i * i; j <= sieve_size; j += i) bs[j] = 0; pr.push_back(i); } } bool is_prime(ll N) { - if (N < sieve_size) return bs[N]; + if (N <= sieve_size) return bs[N]; for (int i = 0; i < pr.size() && pr[i] * pr[i] <= N; ++i) if (N % pr[i] == 0) return false; return true; }