SMMR-236: Missing Skyline

#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,pair<ll,ll>> pii;
int main(){

    ll n;
    priority_queue<pii,vector<pii>,greater<pii>> q;
    //2out 1in
    scanf("%lld",&n);
    for(ll i=0;i<n;i++){
        ll a,b,x;
        scanf("%lld %lld %lld",&a,&b,&x);

        q.push({a,{1,-x}});
        q.push({b,{2,x}});
    }

    ll now_H=-99;
    multiset<ll> sett;
    sett.insert(0);
    while(!q.empty()){
        ll now=q.top().first,  x=q.top().second.first, h=q.top().second.second;
        q.pop();
        //printf("[%lld %lld %lld]\n",now,x,h);
        if(x==1){
            sett.insert(-h);
        }
        else{
            sett.erase(sett.find(h));
        }
        auto itr = sett.end();
        itr--;
        if(*itr!=now_H){
            printf("%lld %lld\n",now,*itr);
            now_H=*itr;
        }

    }

    return 0;
}