下面代码实现了归并排序。下述关于归并排序的说法中，不正确的是（ ）。

void merge(vector<int>& arr, vector<int>& temp, int l, int mid, int r) {
    int i = l, j = mid + 1, k = l;
    while (i <= mid && j <= r) {
        if (arr[i] <= arr[j]) temp[k++] = arr[i++];
        else temp[k++] = arr[j++];
    }
    while (i <= mid) temp[k++] = arr[i++];
    while (j <= r) temp[k++] = arr[j++];
    for (int p = l; p <= r; p++) arr[p] = temp[p];
}

void mergeSort(vector<int>& arr, vector<int>& temp, int l, int r) {
    if (l >= r) return;
    int mid = l + (r - l) / 2;
    mergeSort(arr, temp, l, mid);
    mergeSort(arr, temp, mid + 1, r);
    merge(arr, temp, l, mid, r);
}