java实现归并排序

public class MergeSort {
public static void mergeSort(int[] array) {
if (array.length <= 1) {
return;
}

    int mid = array.length / 2;

    // 分割原始数组为两个子数组
    int[] leftArray = new int[mid];
    int[] rightArray = new int[array.length - mid];
    System.arraycopy(array, 0, leftArray, 0, mid);
    System.arraycopy(array, mid, rightArray, 0, array.length - mid);

    // 递归对子数组进行归并排序
    mergeSort(leftArray);
    mergeSort(rightArray);

    // 合并两个有序子数组
    merge(leftArray, rightArray, array);
}

private static void merge(int[] leftArray, int[] rightArray, int[] mergedArray) {
    int leftLength = leftArray.length;
    int rightLength = rightArray.length;
    int i = 0, j = 0, k = 0;

    while (i < leftLength && j < rightLength) {
        if (leftArray[i] <= rightArray[j]) {
            mergedArray[k++] = leftArray[i++];
        } else {
            mergedArray[k++] = rightArray[j++];
        }
    }

    while (i < leftLength) {
        mergedArray[k++] = leftArray[i++];
    }

    while (j < rightLength) {
        mergedArray[k++] = rightArray[j++];
    }
}

public static void main(String[] args) {
    int[] array = {9, 5, 7, 1, 3, 6, 2, 8, 4};
    System.out.println("原始数组:");
    printArray(array);

    mergeSort(array);

    System.out.println("排序后数组:");
    printArray(array);
}

private static void printArray(int[] array) {
    for (int i : array) {
        System.out.print(i + " ");
    }
    System.out.println();
}

}