【贪心】线段覆盖

 1 #include <iostream>
 2 #include <algorithm>
 3 
 4 using namespace std;
 5 
 6 struct xian
 7 {
 8     int x,y;
 9 };
10 
11 xian a[111];
12 int n;
13 int cmp(xian a,xian b)
14 {
15     return a.y<b.y;
16 }
17 
18 int main()
19 {
20     int x,y;
21     while(cin>>n)
22     {
23         for(int i=0;i<n;i++)
24         {
25             cin>>x>>y;
26             if(x>y)
27                 swap(x,y);
28             a[i].x=x;
29             a[i].y=y;
30         }
31         sort(a,a+n,cmp);
32         int t=0,tem=0;
33         for(int i=0;i<n;i++)
34         {
35             if(a[i].x>=tem)
36             {
37                 t++;
38                 tem=a[i].y;
39             }
40             else
41                 a[i].x=-1;
42         }
43         cout<<t<<endl;
44         for(int i=0;i<n;i++)
45         {
46             if(a[i].x!=-1)
47                 cout<<a[i].x<<" "<<a[i].y<<endl;
48         }
49     }
50     return 0;
51 }