I am trying to implement the Inversion Count problem for merge sort and have implemented it in c++ but I am not getting the desired output. Please help me find the bug in my program:

```
#include <iostream>
using namespace std;
void mergeArr(int a[], int l, int mid, int r)
{
int n1, n2;
int i,j,k;
int inv_count = 0;
n1 = mid - l + 1;
n2 = r - mid;
int temp[r-l+1];
int L[n1], R[n2];
for(i = 0;i < n1;i++)
L[i] = a[l+i];
for(j = 0;j < n2;j++)
R[j] = a[mid+j+1];
i = j = 0;
k = l;
while(i<n1 && j<n2)
{
if(L[i] <= R[j])
temp[k++] = L[i++];
else
{
temp[k++] = R[j++];
inv_count += (mid - i);
}
}
while(i<n1)
temp[k++] = L[i++];
while(j<n2)
temp[k++] = R[j++];
for(i=l;i<=r;i++)
a[i] = temp[i];
}
void mergeSort(int a[], int l, int r)
{
int inv_count = 0;
if(l < r)
{
int mid;
mid = (l + (r))/2;
mergeSort(a,l,mid);
mergeSort(a,mid+1,r);
mergeArr(a,l,mid, r);
}
//return inv_count;
}
int main()
{
cout<<"Enter the number of elements"<<endl;
int n;
cin>>n;
int a[n];
cout<<"Enter the elements: "<<endl;
for(int i=0;i<n;i++)
cin>>a[i];
cout<<"Array before sorting: "<<endl;
for(int i=0;i<n;i++)
cout<<a[i]<<" ";
mergeSort(a,0,n-1);
cout<<endl<<"Array after sorting: "<<endl;
for(int i=0;i<n;i++)
cout<<a[i]<<" ";
//cout<<endl<<"Inversions: "<<mergeSort(a,0,n-1);
return 0;
}
int main()
{
cout<<"Enter the number of elements"<<endl;
int n;
cin>>n;
int a[n];
cout<<"Enter the elements: "<<endl;
for(int i=0;i<n;i++)
cin>>a[i];
cout<<"Array before sorting: "<<endl;
for(int i=0;i<n;i++)
cout<<a[i]<<" ";
/*mergeSort(a,0,n-1);
cout<<endl<<"Array after sorting: "<<endl;
for(int i=0;i<n;i++)
cout<<a[i]<<" ";*/
cout<<"Inversions: "<<mergeSort(a,0,n-1);
return 0;
}
```