/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

4 votes306 views2 answers
Cpp string find all occurence
C++
1 vote307 views3 answers
Arduino get size of array
C++
96 votes429 views4 answers
Change int to string cpp
C++
0 vote249 views1 answer
C++ recorrer string
C++
1 vote296 views1 answer
Right side pattern triangle c++
C++
0 vote257 views1 answer
C++ convert const char* to LPCWSTR
C++
1 vote301 views1 answer
Class Solution { public: vector<vector<int>> threeSum(vector<int>& nums) meaning
C++
0 vote277 views1 answer
Omp multiple reductions
C++
0 vote276 views1 answer
Max pooling in c++
C++
3 votes268 views1 answer
Rick astley - never gonna give you up
C++