下面代码用于归并排序，其中 merge() 函数被调用次数为（ ）。

1#include <iostream>2using namespace std;3 4void mergeSort(int * listData, int start, int end);5void merge(int * listData, int start, int middle, int end);6 7void mergeSort(int * listData, int start, int end) {8    if (start >= end)9        return;10    int middle = (start + end) / 2;11    mergeSort(listData, start, middle);12    mergeSort(listData, middle + 1, end);13    merge(listData, start, middle, end);14}15void merge(int * listData, int start, int middle, int end) {16    int leftSize = middle - start + 1;17    int rightSize = end - middle;18 19    int * left = new int[leftSize];20    int * right = new int[rightSize];21    for (int i = 0; i < leftSize; i++)22        left[i] = listData[start + i];23    for (int j = 0; j < rightSize; j++)24        right[j] = listData[middle + 1 + j];25 26    int i = 0, j = 0, k = start;27    while (i < leftSize && j < rightSize) {28        if (left[i] <= right[j]) {29            listData[k] = left[i];30            i++;31        } else {32            listData[k] = right[j];33            j++;34        }35        k++;36    }37 38    while (i < leftSize) {39        listData[k] = left[i];40        i++;41        k++;42    }43    while (j < rightSize) {44        listData[k] = right[j];45        j++;46        k++;47    }48    delete[] left;49    delete[] right;50}51int main() {52    int lstA[] = {1, 3, 2, 7, 11, 6, 3};53    int size = sizeof(lstA) / sizeof(lstA[0]);54 55    mergeSort(lstA, 0, size - 1); // 对lstA执行归并排序56 57    for (int i = 0; i < size; i++)58        cout << lstA[i] << " ";59    cout << endl;60    return 0;61}