堆 STL

https://blog.csdn.net/qq_41687938/article/details/119257046

#include <bits/stdc++.h>
#include <queue> 
using namespace std;
int n;
int x;
int op;
int main ()
{
    priority_queue<int,vector<int>,greater<int> > c;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>op;
        if(op==1)
        {
            cin>>x;
            c.push(x);
        }
        if(op==2)
        {
            if(!c.empty())
            cout<<c.top()<<endl;
        }
        if(op==3)
        c.pop();
        
    }
    return 0;
}