multiplyVectorByIntegerNaive.cpp

vector<int> addVectors(const vector<int>& a, const vector<int>& b) {
  int maxSize = max(a.size(), b.size());
  vector<int> outputVec(maxSize);
  
  int aIndex = a.size()-1, bIndex = b.size()-1, carry = 0;
  int aVal, bVal;
  
  for (int i = maxSize-1; i >= 0; --i) {
    if (aIndex < 0) aVal = 0;
    else aVal = a[aIndex];
    
    if (bIndex < 0) bVal = 0;
    else bVal = b[bIndex];
    
    outputVec[i] = (aVal + bVal + carry)%10;
    
    if (aVal + bVal + carry > 9) carry = 1;
    else carry = 0;
    
    aIndex--;
    bIndex--;
  }
  
  if (carry) outputVec.insert(outputVec.begin(), 1);
  
  return outputVec;
}

vector<int> multiplyVectorByIntegerNaive(const vector<int>& numVector, int n) {
  vector<int> returnVec = numVector;
  
  while (n != 1) {
    returnVec = addVectors(returnVec, numVector);
    n--;
  }
  
  return returnVec;
}