【leetcode】打印从1到最大的n位数

int* printNumbers(int n, int* returnSize){
    if (n == 0)
        return NULL;
    *returnSize = pow(10,n) - 1;
    int* arr = (int*)calloc(*returnSize,sizeof(int));
    for (int i=0; i<*returnSize; i++)
        arr[i] = i+1;

    return arr;
}