WRONG ANSWER in all the test cases of problem INVERSIONCOUNT

#1

CODE:https://ide.codingblocks.com/s/117408
My code is giving the right output for the given test case and all the possible test cases I could think of. But it is giving wrong answer in the locked test cases. Please tell me which part of my code might be giving the wrong answer.

#2 
#include <bits/stdc++.h>
using namespace std;

#define ll long long

ll k[100005], n;

ll merge(ll *a, ll si, ll ei)
{
     if (si >= ei)
          return 0;

     ll count = 0;
     ll mi = (si + ei) / 2;

     count = count + merge(a, si, mi) + merge(a, mi + 1, ei);

     ll i = si, j = mi + 1;
     ll d = si;

     while (i <= mi && j <= ei)
     {
          if (a[i] <= a[j])
               k[d++] = a[i++];
          else
          {
               k[d++] = a[j++];
               count = count + (mi - i + 1);
          }
     }

     while (i <= mi)
          k[d++] = a[i++];

     while (j <= ei)
          k[d++] = a[j++];

     for (int i = si; i <= ei; i++)
          a[i] = k[i];

     return count;
}

int main()
{
     int t;
     cin >> t;
     while (t--)
     {
          cin >> n;
          ll a[n];
          for (ll i = 0; i < n; i++)
               cin >> a[i];
          cout << merge(a, 0, n - 1) << "\n";
     }
}
#3

please have a look in this code and try to find where you are going wrong.

#4

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