Poistot

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

ll n;
vector<ll> a;
map<ll, vector<ll>> v;
set<pair<ll,ll>> s; //koko, indeksi 
set<ll> indeksit;

int main(){
    cin >> n;
    a.resize(n);
    for(ll i = 0; i < n; i++) cin >> a[i];

    for(ll i = 0; i < n; i++){
        if(s.empty()){
            s.insert({a[i], -i});
            indeksit.insert(i);
            v[i].push_back(a[i]);
            continue;
        }

        auto it = s.lower_bound({a[i], -1e9});

        if(it == s.begin()){
            s.insert({a[i], -i});
            indeksit.insert(i);
            v[i].push_back(a[i]);
        }

        else{

            it--;
            pair<ll,ll> p = *it;
            s.erase(p);
            
            s.insert({a[i], p.second});
            v[-p.second].push_back(a[i]);
        }

        //for(auto j : s) cout << j.first << " " << j.second << endl;
        //cout << endl;
    }

    cout << s.size() << endl;
    for(auto i : indeksit){
        for(auto j : v[i]) cout << j << " ";
        cout << endl;
    }

}

Test 1

Group: 1, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 3

Verdict: ACCEPTED

Test 4

Group: 1, 3

Verdict: ACCEPTED

Test 5

Group: 2, 3

Verdict: ACCEPTED

Test 6

Group: 2, 3

Verdict: ACCEPTED

Test 7

Group: 3

Verdict: ACCEPTED

Test 8

Group: 3

Verdict: ACCEPTED

Test 9

Group: 3

Verdict: ACCEPTED

Test 10

Group: 3

Verdict: ACCEPTED