Arrays 3

gistfile1.txt

vecvector<int> removeDuplicates(vector<int> A)
{
    int j = 0;
    for(int i = 1; i < A.size()-1; i++)
    {
        if (A[i] != A[i-1])
        {
            swap(A[j],A[i]);
            j++;
        }
    }
    while (j < (A.size()-1))
    {
         A.erase(j+1,A.size()-1);
    }
    return A;
}

vector<bool> listPrimes(int num)
{
    // write a function isPrime which checks if a number is prime or not.
    // If it is prime then check for its multiples which are less than num and mark as false

    vector<bool> primes(num+1,true);
    vector<int> result;
    
    int check = 2;
    while (check < num)
    {
        if(primes[check])
        {
            result.emplace_back(check);
            int j = check*2;
            while (j < num)
            {
                j += check;
                result[j] = false;
            }
        }
    }
    return result;
}


//possible optimization: Start seiving and remvoing possibilities from the primes square because all the values before have already been set