在对长度为 $n$（$n \ge 1$）的数组进行归并排序的过程中，mergeArray 函数（合并两个有序子数组的操作）被调用的次数是（ ）。
const int MAXN = 100005;
int a[MAXN];
int tempArr[MAXN];
void mergeArray(int left, int mid, int right) {
int i = left; // 左半部分起点
int j = mid + 1; // 右半部分起点
int k = left; // 临时数组下标
while (i <= mid && j <= right) {
if (a[i] <= a[j]) {
tempArr[k++] = a[i++];
} else {
tempArr[k++] = a[j++];
}
}
while (i <= mid) {
tempArr[k++] = a[i++];
}
while (j <= right) {
tempArr[k++] = a[j++];
}
for (int p = left; p <= right; p++) {
a[p] = tempArr[p];
}
}
void mergeSort(int left, int right) {
if (left >= right) {
return;
}
int mid = left + (right - left) / 2;
mergeSort(left, mid);
mergeSort(mid + 1, right);
mergeArray(left, mid, right);
}