题解 | 分数线划定

#include <iostream>
using namespace std;
#include<vector>
#include<algorithm>
class Student{
    public:
    Student(int id,int grade){
           this->mid=id;
           this->mgrade=grade;
    }
    int mid;
    int mgrade;
};
class mysort{
    public:
    bool operator()(Student s1,Student s2){
        if(s1.mgrade==s2.mgrade){
            return s1.mid<s2.mid;
        }
         return s1.mgrade>s2.mgrade;
    }
};

int main() {
   int m,n;
   cin>>n>>m;
   vector<Student>v;
   while(n--){
    int k,s;
    cin>>k>>s;
    Student stu(k,s);
    v.push_back(stu);
   }
   sort(v.begin(),v.end(),mysort());
    double t=m*1.5;
    t=int(t);
    int t_grade=v[t-1].mgrade;
   // cout<<t<<endl;
     cout<<t_grade<<" ";
      int joinnumber=0;
   for_each(v.begin(),v.end(),[&](Student s){
         if(s.mgrade>=t_grade){
            joinnumber++;
         }
   });
   cout<<joinnumber<<endl;
   for(int i=0;i<joinnumber;i++){
         cout<<v[i].mid<<" "<<v[i].mgrade<<endl;
   }


}
// 64 位输出请用 printf("%lld")