/C++/Prime numbers less than a given number c++

Prime numbers less than a given number c++

// This Function returns a vector containing all primes less than n using seive of eratosthenes
vector<long long> primes_less_than(long long n)
{
    vector<long long> ans(0);
    if (n <= 2)
        return ans;
    map<long long, bool> is_prime;
    for(long long i=0; i < n; i++) 
      	is_prime[i] = true;
    is_prime[0] = false;
    is_prime[1] = false;

    for (long long i = 2; i < sqrt(n); i++)
        if (is_prime[i])
            for (long long j = i * i; j < n; j += i)
                is_prime[j] = false;

    for(long long i=0; i < n; i++)
      	if (is_prime[i] == true) 
          	ans.push_back(i);
    return ans;
}

Similar codes

0 vote305 views1 answer
Honeygain linux
C++
0 vote376 views1 answer
C++ add to array
C++
0 vote335 views1 answer
Bit masking tricks
C++
3 votes325 views4 answers
C++ char array size
C++
2 votes345 views2 answers
Strlen in c++
C++
2 votes311 views1 answer
Java print f int
C++
0 vote344 views1 answer
What is c++ file extension
C++
0 vote346 views1 answer
Gfgdf
C++
0 vote318 views4 answers
Convert java to c++
C++
-1 vote306 views1 answer
How to insert all values from one vector to another
C++