HDU-2037 今年暑假不AC

#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define maxSize 3939
#define _for(i,a,b) for(int i = (a);i < (b);i ++)

struct s
{
    int op;
    int ed;
};

bool cmp(s s1,s s2)
{
    return s1.ed < s2.ed;
}

int main()
{
    vector<s> list;
    int num;
    while(~scanf("%d",&num) && num!=0)
    {
        _for(i,0,num)
        {
            int a,b;
            scanf("%d %d",&a,&b);
            list.push_back(s{a,b});
        }
        
        sort(list.begin(),list.end(),cmp);
        
        int cnt = 0;
        cnt ++;
        int overtime = list[0].ed;
        _for(i,1,num)
        {
            if(list[i].op >= overtime)
            {
                cnt ++;
                overtime = list[i].ed;
            }
        }
        cout << cnt << endl;
        list.clear();
    }
    
    return 0;
}