Codeforces-solutions/TODO.md

# TODO list

List of unsolved problems that I should try again later. Putting everything here to clean
my tabs

## Codeforces

Problem from codeforces.

### Divs

Official divs from codeforces

- Educational

	- [ ] [F. Frogs and Mosquitoes](https://codeforces.com/contest/609/problem/F)

		I have no clue where to even start.

	- [ ] [E. Water Taps](https://codeforces.com/contest/954/problem/E)

		I have an idea, but it's really annoying to solve it.

	- [ ] [F. Fibonacci String Subsequences](https://codeforces.com/contest/946/problem/F)

		Obviously DP, but not sure how to do it...

	- [ ] [F. Imbalance Value of Tree](https://codeforces.com/contest/915/problem/F)

		Tree problem, looks interesting.

	- [ ] [F. Clear The Matrix](https://codeforces.com/contest/903/problem/F)

		DP with optimization?

	- [ ] [D. Sums of Segments](https://codeforces.com/problemset/problem/2026/D)

		Another problem that I didn't have time to finish...

	- [ ] [D. Smithing Skill](https://codeforces.com/problemset/problem/1989/D)

		Yet another problem I couldn't solve on time.
	
	- [ ] [D1. Removal of a Sequence (Easy Version)](https://codeforces.com/contest/2169/problem/D1)

		A josephus problem, I'm gonna need to remember how it works to maka this.

- Global

	- [ ] [E. Journey](https://codeforces.com/contest/2164/problem/E)

		A problem from the global round that I couldn't do during the contest, it's seems to be about
		reconstruction tree, I'll have to see about it.

- Div 1/2

	- [X] [D. Division Versus Addition](https://codeforces.com/contest/2152/problem/D)

		The idea is simple, but I have to think through it better.

	- [ ] [D2. Inversion Graph Coloring](https://codeforces.com/contest/2143/problem/D2)

		DP with optimization.

	- [ ] [E. Yet Another MEX Problem](https://codeforces.com/contest/2146/problem/E)

		Maybe MEX with two pointers?	

	- [ ] [D. A Cruel Segment's Thesis](https://codeforces.com/contest/2140/problem/D)

		Looks greedy.

	- [ ] [F. Flint and Steel](https://codeforces.com/contest/2133/problem/F)

		I tried this a long time ago, don't remember what it's about, just remembered
		that I tried a greedy solution and it didn't work.
	
	- [ ] [C. Music Festival](https://codeforces.com/problemset/problem/1801/C)

		Looks like DP.
	
	- [ ] [C1. Maple and Tree Beauty (Easy Version)](https://codeforces.com/problemset/problem/2138/C1)

		I finished with one type of knapsack, but apparently there's a better way to do
		it that's going to be used to optimize later.
	
	- [ ] [D1. Hot Start Up (easy version)](https://codeforces.com/contest/1799/problem/D1)

		DP, but couldn't do during the simulation...
	
	- [ ] [D. Birthday Gift](https://codeforces.com/problemset/problem/1946/D)

		Another interesting problem that I couldn't do on time.
	
	- [X] [C. How Does the Rook Move?](https://codeforces.com/problemset/problem/1957/C)

		Combinatory problem, managed to get close to the answer but apparently the equation is still
		wrong, need to find the error.
	
	- [X] [C2. Hacking Numbers (Medium Version)](https://codeforces.com/contest/2109/problem/C2)

		Math problem, I feel like I'm closer to an answer.
	
	- [ ] [C. Freedom of Choice](https://codeforces.com/problemset/problem/1893/C)
		
		Doesn't look impossible, but I'm not sure what to do on it, I'll check it out
		in the future.

- Div 3

	- [ ] [G. Cry Me a River](https://codeforces.com/contest/2137/problem/G)

		Graph problem, don't remember the details.
	
	- [ ] [XORificator 3000](https://codeforces.com/problemset/problem/2036/F)

		I had an idea, but didn't have time to implement it.
	
	- [X] [F. Programming Competition](https://codeforces.com/problemset/problem/1914/F)

		Lack of time... Again.
	
	- [ ] [F. Rae Taylor and Trees (hard version)](https://codeforces.com/problemset/problem/2171/F)

		I tried doing it during a simulation but my head didn't want to help me,
		I have to do it eventually when I feel better.
 
- Div 4

	- [ ] [F. Gravity Falls](https://codeforces.com/contest/2148/problem/F)

		I barely read it, not sure were I found it either, but looks pretty easy.

### GYM

Gym from simulations or contests that I did

- ICPC Brazil first phase

	- [ ] [D. Dominoes](https://codeforces.com/gym/106073/problem/D)

		If I did this one, I would have passed into second phase, must try to solve it
		ASAP.

- ICPC Northwestern European Regional

	[Link](https://codeforces.com/gym/104875) because it has no problem page in gym.

	- [ ] L. Last Guess

		I think I can solve it with max flow.

- USP Try-outs

	- [ ] [B. Tuk-Tuk Express](https://codeforces.com/gym/103934/problem/B)

		I have NO clue why my code keeps getting WA, awful implementation problem.

	- [ ] [J. Apep, the Lord of Chaos](https://codeforces.com/gym/103934/problem/J)

		I don't remember what the problem was about, I just know that I tried it before.

- think-cell round 1

	- [X] [C. Lexicographically Largest](https://codeforces.com/problemset/problem/1930/C)
		
		I'll be honest, I just got bored in the middle.

- 2022-2023 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred)

	- [ ] [A. Amazing Trick](https://codeforces.com/problemset/problem/1773/A)

		Once again, didn't finish in time, I didn't even read it to be honest.

- Bubble Cup 9 - Finals [Online Mirror]

	- [ ] [D. Dexterina’s Lab](https://codeforces.com/contest/717/problem/D)

		Got recomended to me.

## Atcoder

- [ ] [F. Operate K](https://atcoder.jp/contests/abc386/tasks/abc386_f)

	DP with optimization.

- [ ] [F - Pyramid Alignment](https://atcoder.jp/contests/abc428/tasks/abc428_f)

	Looks like a good implementation problem.