https://cses.fi/paste/d9ab1dc3493a63706cadc1/
#include <bits/stdc++.h>using namespace std;const int N = 2e5 + 5;int n;int a[N];vector<int> lis;int main() {ios::sync_with_stdio(false), cin.tie(0);cin >> n;for (int i = 1; i <= n; i++) cin >> a[i];for (int i = 1; i <= n; i++) {if (lis.size() == 0 || a[i] > lis.back()) lis.emplace_back(a[i]);else *lower_bound(lis.begin(), lis.end(), a[i]) = a[i];}cout << lis.size() << '\n';}