mergesort astratto vector - internet

#include <iostream>
#include <vector>

using namespace std;

void print(vector<int> v)
{
  for(int i = 0; i < v.size(); i++) cout << v[i] << " ";
  cout << endl;
}

vector<int> merge(vector<int> left, vector<int> right)
{
   vector<int> result;
   while ((int)left.size() > 0 || (int)right.size() > 0) {
      if ((int)left.size() > 0 && (int)right.size() > 0) {
         if ((int)left.front() <= (int)right.front()) {
            result.push_back((int)left.front());
            left.erase(left.begin());
         }
   else {
            result.push_back((int)right.front());
            right.erase(right.begin());
         }
      }  else if ((int)left.size() > 0) {
            for (int i = 0; i < (int)left.size(); i++)
               result.push_back(left[i]);
            break;
      }  else if ((int)right.size() > 0) {
            for (int i = 0; i < (int)right.size(); i++)
               result.push_back(right[i]);
            break;
      }
   }
   return result;
}

vector<int> mergeSort(vector<int> m)
{
   if (m.size() <= 1)
      return m;

   vector<int> left, right, result;
   int middle = ((int)m.size()+ 1) / 2;

   for (int i = 0; i < middle; i++) {
      left.push_back(m[i]);
   }

   for (int i = middle; i < (int)m.size(); i++) {
      right.push_back(m[i]);
   }

   left = mergeSort(left);
   right = mergeSort(right);
   result = merge(left, right);

   return result;
}

int main()
{
   vector<int> v;

   v.push_back(38);
   v.push_back(27);
   v.push_back(43);
   v.push_back(3);
   v.push_back(9);
   v.push_back(82);
   v.push_back(10);

   print(v);
   cout << "------------------" << endl;

   v = mergeSort(v);

   print(v);
}