c++归并排序的实现

以下是C++中归并排序的实现示例：

#include <iostream>
using namespace std;

void merge(int arr[], int l, int mid, int r) {
    int n1 = mid - l + 1;
    int n2 = r - mid;

    int L[n1], R[n2];

    for (int i = 0; i < n1; i++) {
        L[i] = arr[l + i];
    }
    for (int j = 0; j < n2; j++) {
        R[j] = arr[mid + 1 + j];
    }

    int i = 0, j = 0, k = l;

    while (i < n1 && j < n2) {
        if (L[i] <= R[j]) {
            arr[k++] = L[i++];
        } else {
            arr[k++] = R[j++];
        }
    }

    while (i < n1) {
        arr[k++] = L[i++];
    }

    while (j < n2) {
        arr[k++] = R[j++];
    }
}

void mergeSort(int arr[], int l, int r) {
    if (l < r) {
        int mid = l + (r - l) / 2;

        mergeSort(arr, l, mid);
        mergeSort(arr, mid + 1, r);

        merge(arr, l, mid, r);
    }
}

int main() {
    int arr[] = {12, 11, 13, 5, 6, 7};
    int arrSize = sizeof(arr) / sizeof(arr[0]);

    mergeSort(arr, 0, arrSize - 1);

    cout << "Sorted array: ";
    for (int i = 0; i < arrSize; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;

    return 0;
}