快速排序

void qsort(int v[], int left, int right)
{
   int i, last;
   if (left >= right)
        return ;
    swap(v, left, (left + right)/2);
    last = left;
    for ( i= left+1; i<=right; i++)
        if (v[i] < v[left]
            swap(v, ++last; i);
    swap(v, left, last);
    qsort(v, left, last-1);
    qsort(v, last+1, right);
}
void swap(int v[], int i, int j)
{
    int temp;
    temp = v[i];
    v[i] = v[j];
    v[j] = temp;
}