public class Sort {
    public static void mergeSort(int[] arr, int left, int right) {
        if (left < right) {
            int mid = (left + right) / 2;
            mergeSort(arr, left, mid); // 对左子数组进行递归排序
            mergeSort(arr, mid + 1, right); // 对右子数组进行递归排序
            merge(arr, left, mid, right); // 合并两个已排序的子数组
        }
    }
    private static void merge(int[] arr, int left, int mid, int right) {
        int n1 = mid - left + 1;
        int n2 = right - mid;
        int[] leftArr = new int[n1];
        int[] rightArr = new int[n2];
        for (int i = 0; i < n1; i++) {
            leftArr[i] = arr[left + i];
        }
        for (int j = 0; j < n2; j++) {
            rightArr[j] = arr[mid + 1 + j];
        }
        int i = 0;
        int j = 0;
        int k = left;
        while (i < n1 && j < n2) {
            if (leftArr[i] <= rightArr[j]) {
                arr[k] = leftArr[i];
                i++;
            } else {
                arr[k] = rightArr[j];
                j++;
            }
            k++;
        }
        while (i < n1) {
            arr[k] = leftArr[i];
            i++;
            k++;
        }
        while (j < n2) {
            arr[k] = rightArr[j];
            j++;
            k++;
        }
    }
    public static void main(String[] args) {
        int[] array = {5, 2, 8, 12, 1, 6};
        mergeSort(array);
        System.out.println("排序结果：");
        for (int num : array) {
            System.out.print(num + " ");
        }
    }
}