空间复杂度为O(1)的归并排序

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 1 #include <iostream>
 2 #include <cassert>
 3 #include <cmath>
 4 using namespace std;
 5 
 6 //数组反转
 7 void reverse(int *a,int aLength)
 8 {
 9     assert(a);
10     int i=0;
11     int j=aLength-1;
12     while(i<j && i<aLength && j>0)
13     {
14         swap(a[i],a[j]);
15         i++;
16         j--;
17     }
18 }
19 
20 //三次反转实现数组旋转
21 //数组a长度为aLength，将a[0...pos-1]和
22 //a[pos...aLength-1]作位置交换
23 void exchange(int *a,int aLength,int pos)
24 {
25     assert(a);
26     reverse(a,pos);
27     reverse(a+pos,aLength-pos);
28     reverse(a,aLength);
29 }
30 
31 //通过旋转实现merge
32 void Merge(int *a,int aLength,int pos)
33 {
34     assert(a && aLength>0 && pos<=aLength);
35     int i=0;
36     int j=pos;
37     while (j<aLength && i<j)
38     {
39         while (i<j && a[i]<=a[j])
40         {
41                 i++;
42         }
43         int maxMove=0;
44         while (j<aLength && a[i]>a[j])
45         {
46             maxMove++;
47             j++;
48         }
49         exchange(a+i,j-i,j-i-maxMove);
50         i+=maxMove;
51     }
52 }
53 
54 void print(int *a,int aLength)
55 {
56     for (int i=0;i<aLength;i++)
57     {
58         cout<<a[i]<<"  ";
59     }
60     cout<<endl;
61 }
62 int main()
63 {
64     const int aLength=8;
65     int a[aLength]={1,6,8,19,2,3,23,35};
66     Merge(a,aLength,4);
67     print(a,aLength);
68 }

参考文章：http://www.cppblog.com/converse/archive/2008/09/28/63008.html

posted @ 2012-07-14 16:39  kasuosuo  阅读(564)  评论(0)  编辑  收藏  举报