#include<bits/stdc++.h>
using namespace std;
int main(){int p,x;multiset<int>s;
    for (cin>>p;cin>>p;){
        if(p==1)cin>>x,s.insert(x);
        if(p==2)cout<<*s.begin()<<"\n";
        if(p==3)cout<<*s.rbegin()<<"\n";
        if(p==4)s.erase(s.begin());
        if(p==5)s.erase(--s.end());
    }
}

一份使用multiset的极简解