注：本博文来自Yang Enzo博客园，感谢作者整理。

 

:Introduction to Algorithms P95

T(n) = 3 * T(2*n/3) + O(1)

According to master method,this situation suits the first case.

 1 ///////////////////Test Code/////////////////////////
 2 #include "stdafx.h"
 3 #include "stdlib.h"
 4 #include <time.h>
 5 #include "basic_algorithm.h"
 6 #include <iostream>
 7 using namespace std;
 8 
 9 
10 int _tmain(int argc, _TCHAR* argv[])
11 {
12     
13     srand((unsigned)time(NULL));
14     int *arr = new int[20];
15     for(int i = 0; i < 20; ++i)
16     {
17         arr[i] = rand() % 30;
18     }
19     enzo::stooge_sort(arr,20);
20     for(int i = 0; i < 20; ++i)
21     {
22         cout << arr[i] << " ";
23     }
24     cout << endl;
25     system("pause");
26     return 0;
27 }
28 
29 ///////////////////Source Code///////////////////////
30     template<typename _T>
31     void stooge_sort(_T *arr, int n)
32     {
33         stooge_sort(arr, 0, n-1);
34     }
35 
36     template<typename _T>
37     void stooge_sort(_T *arr, int from, int to)
38     {
39         if(arr[to] < arr[from])
40         {
41             ez_swap(arr[to], arr[from]);
42         }
43         if(from + 1 < to)
44         {
45             int k = (to - from + 1) / 3;
46             stooge_sort(arr, from, to - k);
47             stooge_sort(arr, from + k, to);
48             stooge_sort(arr, from, to - k);
49         }
50     }

 


T(n) = O(n^(log(2/3, 3) > O(n^2)