quickSort in-place version whose space complexity is O(log(N))

 1 public void quickSortSwapping(int data[]){
 2 //call this method
 3 quickSortSwapping(data,0,data.length);
 4 }
 5
 6
 7 public void quickSortSwapping(int data[],int start,int len){
 8 if(len<2)return;
 9 int pivotIndex=start+len/2;
10 int pivotValue=data[pivotIndex];
11 int end=data.length;
12 int cur=start;
13
14 //swapping the pivot to the end of array,for the testcase [a,a,a,a,a,a](PIE p130)
15
16 swap(data,pivotIndex,--end);
17
18 //partiton the rest of array
19 while(cur<end){
20
21 if(data[cur]<pivotVaule){
22
23 cur++;
24
25 }else{
26
27 swap(data,cur,--end);
28
29 }
30
31 //put pivot back to the original place
32
33 swap(data,end,start+len-1);
34
35 //using recursive method to partition ench part
36
37 int llen=end-start;
38 int rlen=len-llen-1;
39
40 if(llen>1){
41
42 quickSortSwapping(data,start,llen);
43 }
44
45 if(rlen>1){
46
47 quickSortSwapping(data,end+1,rlen);
48 }
49 }
50
51
52 }