A self-dividing number is a number that is divisible by every digit it contains.
 For example, 128 is a self-dividing number because 128 % 1 == 0, 128 % 2 == 0, and 128 % 8 == 0.
 Also, a self-dividing number is not allowed to contain the digit zero.
 Given a lower and upper number bound, output a list of every possible self dividing number, including the bounds if possible.

Example 1:
 Input:
left = 1, right = 22
 Output: 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 15, 22 

bool isDividingNumbers(int num)
{
    int tmp = num;
    int dig = 0;
    
    while(tmp)
    {
        dig = tmp % 10;
        if(0 == dig || num % dig)
            return false;
        tmp /= 10;
    }
    
    return true;
}

/**
 * Return an array of size *returnSize.
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* selfDividingNumbers(int left, int right, int* returnSize) 
{
    *returnSize = 0;
    int k = 0;
    for(int i = left;i <= right;i++)
    {
        if(isDividingNumbers(i))
            (*returnSize)++;
    }
    
    int *res = (int *)malloc(*returnSize * sizeof(int));
    
    for(int i = left;i <= right;i++)
    {
        if(isDividingNumbers(i))
            res[k++] = i;
    }
    
    return res;
    
}

bool isDividingNumbers(int num)
{
    int tmp = num;
    int dig = 0;
    
    while(tmp)
    {
        dig = tmp % 10;
        if(0 == dig || num % dig)
            return false;
        tmp /= 10;
    }
    
    return true;
}

/**
 * Return an array of size *returnSize.
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* selfDividingNumbers(int left, int right, int* returnSize) 
{
    *returnSize = 0;
    int size = 32;
    /*malloc 32 int at begin*/
    int *res = (int *)malloc( size * sizeof(int));
    
    for(int i = left;i <= right;i++)
    {
        if(isDividingNumbers(i))
        {
            if((*returnSize + 1) % 31==0)
            {
                size += 32;
                res = (int *)realloc(res,sizeof(int)*size);
            }
            res[(*returnSize)++] = i;
              
        }
              
    }
    
    return res;
    
}

第二种方法使用了realloc函数，两种方法在leetcode上的执行时间均为4ms.