1: /*
2: *Author:justinzhang
3: *Email:uestczhangchao@gmail.com
4: *Time:2011年5月11日15:58:40
5: *Discription:算法导论第7章，快速排序算法实现
6: change the previous c to cpp, and using template to make satisfy more data type
7: @Justin at:2012-9-4 21:57:52
8: */
9:
10: #include <iostream>
11: using namespace std;
12: /*交换两个数*/
13: template <typename T> void q_swap(T &x, T& y)
14: { 15: T tmp = x;
16: x = y;
17: y= tmp;
18: }
19:
20: /*以数组的最右边元素A[r]为主元对数组进行划分，返回pivot，pivot左边的元素都比A[r]小，右边的元素
21: *都比A[r]大；
22: */
23: template <typename T> int partition(T A[],int p, int r)
24: { 25: T x = A[r];
26: int i=p-1;
27: int j;
28: for(j=p;j<=r-1;j++)
29: { 30: if(A[j]<x)
31: { 32: i++;
33: q_swap<T>(A[i],A[j]);
34: }
35: }
36: i++;
37: q_swap(A[i],A[r]);
38: return i;
39: }
40:
41: /*利用partition不断的对数组进行划分，然后分别对划分后的两个部分进行排序(分治法思想)*/
42: template <typename T> void quicksort(T A[],int low, int high)
43: { 44: int pivot;
45: if(low<high)
46: { 47: pivot = partition<T>(A,low,high);
48: quicksort(A,low,pivot-1);
49: quicksort(A,pivot+1,high);
50: }
51:
52: }
53:
54: int main()
55: { 56: /*这里数组的下标从0开始*/
57: int A[]={55,5,4,6,7,8,-444,4}; 58: int i;
59: quicksort<int>(A,0,7);
60: for(i=0;i<=7;i++)
61: cout << A[i] << endl;
62:
63: /*----test double qsort----------*/
64: cout << "test double quicksrot" << endl;
65: double data[] = {1.0, -2.0, 3.0,4.5}; 66: quicksort<double>(data ,0, sizeof(data)/sizeof(double)-1);
67:
68: for(i=0;i<=sizeof(data)/sizeof(double)-1;i++)
69: cout << data[i] << endl;
70:
71: return 0;
72: }
73:
