quicksort 不知道为什么达不到效果啊，超时......

[eks_222]

void quickSort(string *a, int left, int right)
{
if(left>=right)
return;
int i = left - 1;
string b = a[right];
for(int j=left; j<right; j++)
{
if(a[j]<b)
{
i++;
string c = a[j];
a[j] = a[i];
a[i] = c;
}
}
a[right]= a[i+1];
a[i+1] = b;

quickSort( a, left, i);
quickSort( a, i+2, right);
return;
}

这是我照着伪代码写的quicksort，可是不知道为什么时间复杂度好像不低啊
分析不了......菜鸟一个，呵呵，麻烦帮忙看一下

[qap22]

不懂，up

[NaWait]

best case of quick sort:
Q(n) = 2Q(n/2) + n/2 if n>=2
Q(n) = 1 if n<=1

當n = k 時

Q(k) = 2(2(2( ...... )+k/8)+k/4)+ k/2

= (logk) * (k/2)

= O(klogk)

worst case of quick sort:
Q(n) = Q(n-1) + (n-1) if n>=2
Q(n) = 1 if n<=1

當n = k 時

Q(k) = (k-1)+(k-2)+....+1 = O(n^2)