quicksort

快排。。。。

void quicksort(int *a,int left,int right){
    if(left >= right){
        return ;
    }
    int i = left;
    int j = right;
    int key = a[left];

    while(i < j)
    {
        while(i < j && key <= a[j]){
            j--;
        }
        a[i] = a[j];
        while(i < j && key >= a[i]){
            i++;
        }

        a[j] = a[i];
    }

    a[i] = key;
    quicksort(a, left, i - );
    quicksort(a, i + , right);
}