题解 | 两端问优先队列

#include <iostream>
#include<set>
#include <sys/types.h>
using namespace std;

int main() {
    multiset<int> heap;
    int n; cin >> n;
    for(int i = 0; i < n; i++) {
        int op,x; cin >> op;
        if(op == 1) {
            cin >> x;
            heap.insert(x);
            continue;
        }
        if(op == 2) {
            if(!heap.empty()) {
                cout << *heap.begin() << endl;
            }
            continue;
        }
        if(op == 3) {
            if(!heap.empty()) {
                cout << *(--heap.end()) << endl;
            }
            continue;
        }
        if(op == 4) {
            if(!heap.empty()) {
                heap.erase(heap.begin());
            }
            continue;
        }
        if(op == 5) {
            if(!heap.empty()) {
                heap.erase(--heap.end());
            }
            continue;
        }
    }
}
// 64 位输出请用 printf("%lld")