下面代码用于归并排序，其中 merge() 函数被调用次数为（ ）：

#include <iostream>
using namespace std;
void mergeSort(int * listData, int start, int end);
void merge(int * listData, int start, int middle, int end);

void mergeSort(int * listData, int start, int end) {
    if (start >= end)
        return;
    int middle = (start + end) / 2;
    mergeSort(listData, start, middle);
    mergeSort(listData, middle + 1, end);
    merge(listData, start, middle, end);
}
void merge(int * listData, int start, int middle, int end) {
    int leftSize = middle - start + 1;
    int rightSize = end - middle;

    int * left = new int[leftSize];
    int * right = new int[rightSize];
    for (int i = 0; i < leftSize; i++)
        left[i] = listData[start + i];
    for (int j = 0; j < rightSize; j++)
        right[j] = listData[middle + 1 + j];

    int i = 0, j = 0, k = start;
    while (i < leftSize && j < rightSize) {
        if (left[i] <= right[j]) {
            listData[k] = left[i];
            i++;
        } else {
            listData[k] = right[j];
            j++;
        }
        k++;
    }
    while (i < leftSize) {
        listData[k] = left[i];
        i++;
        k++;
    }
    while (j < rightSize) {
        listData[k] = right[j];
        j++;
        k++;
    }
    delete[] left;
    delete[] right;
}
int main() {
    int lstA[] = {1, 3, 2, 7, 11, 5, 3};
    int size = sizeof(lstA) / sizeof(lstA[0]);
    mergeSort(lstA, 0, size - 1);
    for (int i = 0; i < size; i++)
        cout << lstA[i] << " ";
    cout << endl;
    return 0;
}