归并排序（mergeSort） 

 1 #include <iostream>
 2 #include <vector>
 3 #include <algorithm>
 4 using namespace std;
 5 
 6 void mergeLocal(int arr[], int low, int middle, int high)
 7 {
 8     int i, j, k;  //i and j respectively represent the current position of the two subsequences to be merged
 9     i = low;
10     j = middle + 1;
11     k = 0;
12     int b[high-low+1];
13     while(i<=middle&&j<=high)
14     {
15         if(arr[i]<=arr[j]) //the smaller subsequence is placed on the front
16         {
17           b[k] = arr[i];
18           k++;
19           i++;
20         }
21         else
22         {
23             b[k] = arr[j];
24             k++;
25             j++;
26         }
27     }
28     while(i<=middle)  //if the subsequence of the leading position is not empty, copy the remainder to b
29     {
30         b[k] = arr[i];
31         k++;
32         i++;
33     }
34     while(j<=high)  //if the subsequence of the back position is not empty, copy the remainder to b
35     {
36         b[k] = arr[j];
37         k++;
38         j++;
39     }
40     for(int p=low, h=0; p<=high; p++, h++)
41     {
42         arr[p] = b[h];
43     }
44     return;
45 }
46 
47 void mergeSort(int a[], int low, int high)
48 {
49     int middle;
50     if(low<high)
51     {
52         middle = (low + high) / 2;
53         mergeSort(a, low, middle);
54         mergeSort(a, middle+1, high);
55         mergeLocal(a, low, middle, high);
56     }
57     return;
58 }
59 int main()
60 {
61     int a[] = {57, 68, 23, 90, 78, 32, 96, 13, 9, 45};
62     mergeSort(a, 0, 9);
63     for(int i=0; i<10; i++)
64         cout << a[i] << " ";
65     return 0;
66 }

 

posted @ 2017-09-25 16:25  diamondDemand  阅读(296)  评论(0)    收藏  举报