【leetcode】强整数

int cmp(const void* a, const void* b)
{
    return *(int*)a - *(int*)b;
}
int* powerfulIntegers(int x, int y, int bound, int* returnSize){
    if (bound<2)
    {
        *returnSize = 0;
        return NULL;
    }
    int* arr = (int*)calloc(bound,sizeof(int));
    int i,j,xMax=1,yMax=1,n=0,m=1;
    if (x !=1)
    {
        for (i=1; i<=bound && pow(x,i)<=bound; i++);  //找出x对应次方的最大范围
        xMax = i;
    }
    if (y != 1)
    {
        for (i=1; i<=bound && pow(y,i)<=bound; i++);  //找出y对应次方的最大范围
        yMax=i;
    }
    for (i=0; i<xMax; i++)
    {
        for (j=0; j<yMax && pow(x,i) + pow(y,j) <= bound; j++)
        {
            arr[n++] = pow(x,i) + pow(y,j);
        }
    }
    qsort(arr,n,sizeof(int),cmp);
    for (i=1; i<n; i++)
    {
        if (arr[i] != arr[i-1]) arr[m++] = arr[i]; //去掉重复的数
    }
    *returnSize = m;
    return arr;
}