This is my code for counting inverrsion pair i have modified the logic from counting inversion pairs but it is not working could you please point out why?

int cnt = 0;

void merge(vector<int> &a, int low, int mid, int high) {
  vector<int> temp;
  int left = low;
  int right = mid + 1;
  while (left <= mid && right <= high) {
    if (a[left] <= a[right]) {
      temp.push_back(a[left]);
      left++;
    } else {
      if (a[left] > 2 * a[right] && left <right) {
        cnt += mid - left + 1;
      }
      temp.push_back(a[right]);
      right++;
    }
  }

  while (left <= mid) {
    temp.push_back(a[left]);
    left++;
  }
  while (right <= high) {
    temp.push_back(a[right]);
    right++;
  }

  for (int i = low; i <= high; i++) {
    a[i] = temp[i - low];
  }
  for (int i = low; i <= high; i++) {
    cout << a[i] << " ";
  }
  cout << cnt << endl;
}

void mergesort(vector<int> &a, int low, int high) {
  if (low >= high)
    return;
  int mid = low + (high - low) / 2;
  mergesort(a, low, mid);
  mergesort(a, mid + 1, high);
  merge(a, low, mid, high);
}

int team(vector<int> &a, int n) {
  mergesort(a, 0, n - 1);
  return cnt;
}

why is this not working the answer for the testcase 4 1 2 3 1 is 3 is am getting 2 in this code ?