_(:з」∠)_
1 #include <cstdio>
2 #include <iostream>
3 #include <ctime>
4 #include <windows.h>
5 #include <algorithm>
6 #include <fstream>
7 using namespace std;
8 struct activity
9 {
10 int no;
11 int start;
12 int finish;
13 };
14 bool cmp(const activity &x, const activity &y)
15 {
16 return x.finish<y.finish;//从小到大排<，若要从大到小排则>
17 }
18 int greedySelector(int m,int solution[],struct activity activity[]){
19 int number = 1;
20 solution[0] = 1;
21 int i,j = 0,counter = 1;
22 for(i = 1;i < m ;i++)
23 {
24 if(activity[i].start >=activity[j].finish)
25 {
26 solution[i] = 1;
27 j = i;
28 counter++;
29 }
30 else
31 solution[i] = 0;
32 }
33 cout << "The amount of activities is:"<<counter<<endl;
34 cout << "The solution is:";
35 for(i = 0 ;i < m ;i++)
36 {
37 if (solution[i] == 1)
38 {
39 cout << activity[i].no <<" ";
40 }
41 }
42 return counter;
43 }
44 int main(void)
45 {
46 LARGE_INTEGER nFreq;
47 LARGE_INTEGER nBeginTime;
48 LARGE_INTEGER nEndTime;
49 ofstream fout;
50 srand((unsigned int)time(NULL));
51 int m,i,j,t;
52 double cost;
53 cout << "Please enter the number of times you want to run the program:";
54 cin >> t;
55 fout.open("activity.txt",ios::app);
56 if(!fout){
57 cerr<<"Can not open file 'activity.txt' "<<endl;
58 return -1;
59 }
60 fout.setf(ios_base::fixed,ios_base::floatfield); //防止输出的数字使用科学计数法
61 for (j = 0;j < t;j++)
62 {
63 cout << "——————————————————The "<< j + 1 << "th test —————————————————"<<endl;
64 m = 1 + rand()%100000;
65 fout<<m<<",";
66 int solution[m];
67 activity activity[m];
68 for( i = 0;i < m;i++)
69 {
70 activity[i].no = i+1;
71 activity[i].start = 1 + rand()%1000;
72 while(1)
73 {
74 activity[i].finish = 1 + rand()%10000;
75 if(activity[i].finish > activity[i].start) break;
76 }
77 }
78 QueryPerformanceFrequency(&nFreq);
79 QueryPerformanceCounter(&nBeginTime);
80 sort(activity,activity+m,cmp);
81 greedySelector(m,solution,activity);
82 QueryPerformanceCounter(&nEndTime);
83 cost=(double)(nEndTime.QuadPart - nBeginTime.QuadPart) / (double)nFreq.QuadPart;
84 fout << cost << endl;
85 cout << "\nThe running time is:" << cost << " s" << endl;
86 }
87 fout.close();
88 cout << endl << endl;
89 cout << "Success!" << endl;
90 return 0;
91 }