I was trying to solve IZHO14_bank on oj.uz. In problem $$$n, m <= 20$$$ and Time Limit is 1s.

Time complexity of my solution is $$$O(2^m \cdot m \cdot n)$$$. It's $$$TLE$$$ because $$$2^{20} \cdot 20 \cdot 20 = 419 430 400 > 10^8$$$.

My both code have same time complexity but my $$$1^{st}$$$ code is $$$TLE$$$, $$$2^{nd}$$$ got $$$100$$$ score.

Can someone explain why my $$$2^{nd}$$$ code isn't $$$TLE$$$ $$$?$$$
$$$1^{st}$$$ submission https://oj.uz/submission/854216 gives $$$TLE$$$,
$$$2^{nd}$$$ submission https://oj.uz/submission/854864 got $$$100$$$ score.

4 months ago, I posted a blog hoping to find OI groups on CF since most sites are blocked in my country. Unfortunately couldn't find.

In CF blogs, for practicing to OIs, suggested is solving easier OIs. But I have only CF with 2017-2023 IZHO, 2002-2023 IOI, and from gym. I can get some points on IZHO, but IOI is hard for me.

Is CF enough to get medal at IZHO, IOI?
In which rating I'll be able to solve(get points on) IOI problems?
In which rating I'll be able to get bronze, silver, gold at IZHO, IOI?

In my country many sites are blocked.

Luckily Codeforces isn't blocked in my country, and I'm looking for OI groups on CF.

If you know such groups please comment it. It will be very helpful.