/C++/Prime factorisation of a number in c++

Prime factorisation of a number in c++

// Function that returns a vector containing all the prime factors of n (25 --> 5, 5)
vector<long long> prime_factorisation(long long n)
{
    //spf is smallest prime factor
    map<long long, long long> spf;
    vector<long long> ans(0);
    for(long long i = 2; i <= n; i++) spf[i] = i;

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

    while (n != 1)
    {
        ans.push_back(spf[n]);
        n /= spf[n];
    }
    return ans;
}

Similar codes

2 votes166 views3 answers
C++ lambda
C++
0 vote249 views1 answer
Operator overloading outside class
C++
15 votes167 views4 answers
C++ vector
C++
0 vote195 views1 answer
Esp
C++
0 vote164 views1 answer
C++ unittest in ros
C++
0 vote176 views1 answer
Convert characters to lowercase c++
C++
9 votes159 views9 answers
Selection sort
C++
1 vote163 views2 answers
Ue4 array copy c++
C++
3 votes211 views3 answers
C++ string contains
C++
0 vote198 views1 answer
Sort vector of strings
C++