Quick sort count comparison

#include <algorithm>
#include <bitset>
#include <cstring>
#include <cctype>
#include <cmath>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <string>
#include <set>
#include <stack>
#include <stdio.h>
#include <sstream>
#include <utility>
#include <vector>
#define INT_MAX 2147483647
#define INT_MIN -2147483648
#define pi acos(-1.0)
#define N 1000000
#define LL long long

using namespace std;

int comparisonCount = 0;

int chooseMedianOfThreeAsPivot(int a[],int start, int end) {

        int pivotIndex = -1;

        int mid = ((end - start) / 2) + start;
        int b[3];
        b[0] = a[start];
        b[1] = a[mid];
        b[2] = a[end];

        sort(b,b+3);
        if (b[1] == a[start]) {
            pivotIndex = start;
        }else if(b[1] == a[mid]) {
            pivotIndex = mid;
        }else {
            pivotIndex = end;
        }

        // Move pivot to start index.
        int temp = a[start];
        a[start] = a[pivotIndex];
        a[pivotIndex] = temp;

        return start;
}

int partition(int a[],int l,int r,int pivotIndex)
{
    int arrayLength = r - l;
    comparisonCount += arrayLength;
    int p,i,j;
    p = a[pivotIndex];
    i = l+1;
    for(j=l+1;j<=r;j++)
    {
        if(a[j]<p)
        {
             int t = a[i];
             a[i] = a[j];
             a[j] = t;
             i++;
        }
    }
    int t=a[l];
    a[l] = a[i-1];
    a[i-1] = t;
    return i-1;
}

void quick_sort(int *a,int l,int r)
{
    if (r <= l) {
            return;
        }
    if(l<r)
    {
        int pivotIndex = chooseMedianOfThreeAsPivot(a,l,r);
        int s = partition(a,l,r,pivotIndex);
        quick_sort(a,l,s-1);
        quick_sort(a,s+1,r);

    }
}

int main()
{
    #ifndef ONLINE_JUDGE
       freopen("data.txt", "r", stdin);
       freopen("output.txt","w",stdout);
    #endif

    int array[100005];
    for(int i=0;i<10000;i++)
        cin>>array[i];

   // partition(array,1,10000);
    quick_sort(array,0,9999);

    for(int i=0;i<10000;i++)
        cout<<array[i]<<"\n";

    cout<<"\n\n\n";
    cout<<comparisonCount<<"\n";
return 0;
}