c++快速排序

 1 #include<iostream>
 2 #include<ctime>
 3 using namespace std;
 4 
 5 
 6 int RandomInRange(int start, int end) {
 7     srand((unsigned)time(NULL));
 8     int value = rand()% (end - start + 1) + start;
 9     return value;
10 }
11 
12 void Swap (int *a, int *b) {
13     int temp;
14     temp = *a;
15     *a = *b;
16     *b = temp;
17 }
18 int Partition(int data[], int length, int start, int end) {
19     if(data == NULL || length <= 0 || start < 0 || end >= length) {
20         throw new std::exception("Invaild Parameters");
21     }
22 
23     int index = RandomInRange(start, end);
24     Swap(&data[index], &data[end]);//将选取的数字放到最后
25 
26     int small = start - 1;
27     for(index = start; index < end; index++) {//此处是从一边遍历，另外可以从两边开始遍历
28         if(data[index] < data[end]) {
29             ++small;//位置在small之前的数字，都是比选取的数字小的
30             if(small != index)
31                 Swap(&data[index], &data[small]);
32         }
33     }
34     ++small;
35     Swap(&data[small], &data[end]);//最后将选取的数字放到合适的位置
36     return small;
37 }
38 
39 void QuickSort(int data[], int length, int start, int end) {
40     if(start == end)
41         return;
42     int index = Partition(data, length, start, end);
43     if (index > start)
44         QuickSort(data, length, start, index-1);
45     if (index < end)
46         QuickSort(data, length, index+1, end);
47 }
48 int main()
49 {
50     //cout << RandomInRange(1, 10) << endl;
51     int data[] = {2,4,3,1,5,7,6};
52     QuickSort(data, 7, 0, 6);
53     for(int i = 0; i < 7; i++) {
54         cout << data[i] << endl;
55     }
56     return 0;
57 }