(Searching and Sorting) Room Allocation

#include <bits/stdc++.h>
using namespace std;
 
#define int long long 
const long long  mod =1e9+7;
 
using namespace std;


int32_t main(){
    int n;
    cin>>n;
    vector<pair<pair<int, int>,int> > vec(n);
    for(int i=0 ;i<n; i++){
        cin>>vec[i].first.first>>vec[i].first.second;
        vec[i].second=i;
    }
    sort(vec.begin(), vec.end());
    vector<int> ans(n);
    int curr=0, total=0;
    priority_queue<pair<int, int>> pq;
    for(int i=0; i<n; i++){
        if(pq.empty()){
            curr++;
            pq.push({-1*vec[i].first.second, curr});
            ans[vec[i].second]=curr;
        }else{
            pair<int, int> v = pq.top();
            if(-1*v.first<vec[i].first.first){
                pq.pop();
                pq.push({-1*vec[i].first.second, v.second});
                ans[vec[i].second]=v.second;
            }else{
                curr++;
                pq.push({-1*vec[i].first.second, curr});
                ans[vec[i].second]=curr;
            }
        }
        total=max(curr, total);
    }
    cout<<total<<endl;
    for(int i=0 ;i<n; i++){
        cout<<ans[i]<<" ";
    }
    return 0;
}