getMinP

std::vector<int> getMinP(int n) {
  std::vector<int> primes;
  std::vector<int> minp(n + 1);
  for (int i = 2; i <= n; ++i) {
    if (minp[i] == 0) {
      minp[i] = i;
      primes.push_back(i);
    }
    for (auto& prime : primes) {
      if (prime * i > n) {
        break;
      }
      minp[prime * i] = prime;
      if (i % prime == 0) {
        break;
      }
    }
  }
  return minp;
}