【排序】冒泡排序+快速排序

冒泡排序：

 1 //复杂度：O(n^2)

 2 //比较次数：n*(n-1)/2 ；移动等数量级

 3 #include<iostream>

 4 #include<cstdio>

 5 #include<cstdlib>

 6 using namespace std;

 7 const int INF = 0x7fffffff;

 8 void Bubble_sort(int* A, int n)

 9 {

10     for(int i = n-1; i >= 0; i--)

11     {

12         A[n] = A[i];

13         int _max = -INF, pos = -1;

14         for(int j = 0; j <= i; j++)

15         {

16             if(_max < A[j]) _max = A[j], pos = j;

17         }

18         A[pos] = A[n];

19         A[i] = _max;

20     }

21     for(int i = 0; i < n; i++)  {if(i) printf(" "); printf("%d", A[i]);}

22     printf("\n");

23 }

24 

25 int main()

26 {

27     int A[10] = {1, 9, 3, 7, 5, 2, 8, 4, 6, 10};

28     Bubble_sort(A, 10);

29     return 0;

30 }

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快速排序：

 1 //一趟排序将待排记录分割成独立的两部分，其中一部分记录的关键字均比另一部分记录的关键字小，

 2 //则可分别对这两部分记录继续进行排序，以达到整个序列有序

 3 //复杂度：O(nlnn)

 4 #include<iostream>

 5 #include<cstdio>

 6 #include<cstdlib>

 7 #include<list>

 8 using namespace std;

 9 //改进前

10 //void Exchange(int* L, int i, int j)

11 //{

12 //    int tmp = L[i]; L[i] = L[j]; L[j] = tmp;

13 //}

14 

15 int Partition(int* L, int low, int high){

16     L[0] = L[low];

17     int pivotkey = L[low];

18     while(low < high)

19     {

20         while(low < high && L[high] >= pivotkey) high--;

21         //Exchange(L, low, high);

22         L[low] = L[high];

23         while(low < high && L[low] <= pivotkey) low++;

24         //Exchange(L, low, high);

25         L[high] = L[low];

26     }

27     L[low] = L[0];

28     return low;//返回枢轴所在位置

29 }

30 void Quick_sort(int* L, int low, int high)

31 {

32     if(low >= high)  return ;

33     int pivotkey = Partition(L, low, high);

34     Quick_sort(L, low, pivotkey-1);

35     Quick_sort(L, pivotkey+1, high);

36 }

37 

38 int main()

39 {

40     int L[11] = {0, 3, 9, 1, 7, 5, 2, 8, 4, 6, 10};

41     Quick_sort(L, 1, 10);

42     for(int i = 1; i <= 10; i++) {if(i) printf(" "); printf("%d", L[i]);}

43     printf("\n");

44     return 0;

45 }