ural 1203. Scientific Conference

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define maxn 400000
 5 using namespace std;
 6 
 7 struct node
 8 {
 9     int s,e;
10     bool operator <(const node &a)const
11     {
12         return ((e<a.e)||(e==a.e&&s>a.s));
13     }
14 }p[maxn];
15 int dp[maxn];
16 
17 int main()
18 {
19     int n;
20     scanf("%d",&n);
21     for(int i=1; i<=n; i++)
22     {
23         scanf("%d%d",&p[i].s,&p[i].e);
24     }
25     sort(p+1,p+n+1);
26     int e=0,s=0;
27     int cnt=0;
28     for(int i=1; i<=n; i++)
29     {
30         if(p[i].s>=s)
31         {
32             s=p[i].e+1;
33             cnt++;
34         }
35     }
36     printf("%d\n",cnt);
37     return 0;
38 }