Time Limit Randomized Quicksort

#include <iostream>
#include <vector>
#include <cstdlib>
#include <iterator>
#include <utility>
 
using namespace std;
 
template <typename T>
void swaping (T &a, T &b)
{
    T c;
    c = a;
    a = b;
    b = c;
}
 
template<class RandomAccessIterator>
RandomAccessIterator partitioning (RandomAccessIterator first,
                             RandomAccessIterator last)
{
    RandomAccessIterator beg = first - 1;
    int pivot = *(last - 1);
 
    for (RandomAccessIterator end = first; end != last - 1; ++end)
 
        if (*end < pivot + 1)
        {
            ++beg;
            swaping (*beg, *end);
        }
 
    swaping (*(beg + 1), *(last - 1));
    return (beg + 1);
 
}
 
template<class RandomAccessIterator>
RandomAccessIterator random_partitioning (RandomAccessIterator first,
                                    RandomAccessIterator last)
{
    RandomAccessIterator random_iterator = rand()% (last - first - 1) + first;
    swaping (*(random_iterator), *(last - 1));
    return partitioning<RandomAccessIterator> (first, last);
}
 
template<class RandomAccessIterator>
void quick_sort (RandomAccessIterator first,
                 RandomAccessIterator last)
{
    if (first < last - 1)
    {
        RandomAccessIterator median = random_partitioning<RandomAccessIterator> (first, last);
        quick_sort<RandomAccessIterator> (first, median);
        quick_sort<RandomAccessIterator> (median + 1, last);
    }
}
 
template <class RandomAccessIterator>
void quick_sortn (RandomAccessIterator first, RandomAccessIterator last)
{
    while (first < last - 1)
    {
        RandomAccessIterator median = random_partitioning<RandomAccessIterator> (first, last);
        if (median - first < last - median)
        {
            quick_sortn(first, median);
            first = median + 1;
        }
        else
        {
            quick_sortn(median, last);
            last = median;
        }
    }
}
 
int main ()
{
    int size;
    cin >> size;
    vector <int> v;
 
    for (int i = 0; i < size; ++i)
    {
        int inp;
        cin >> inp;
        v.push_back(inp);
    }
 
    //vector <int>::iterator first = v.begin();
    //vector <int>::iterator last = v.end() - 1;
 
    cout << endl;
 
    cout << endl << endl;
 
    quick_sortn<vector <int>::iterator> (v.begin(), v.end());
 
    cout << endl;
 
 
    for (vector <int>::iterator it = v.begin(); it < v.end(); ++it) cout << *it << ' ';
 
    return 0;
}