6.0 KiB
Problem List
A little collection of interesting problems that I randomly decided to do.
Ad-hoc/Greedy
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B. Gellyfish and Baby's Breath
Cool ad-hoc problem, a little of math but mostly greedy.
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One of the most annoying problem I did, good to prepare for the future hell.
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Another incredibly annoying problem, beware...
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[D. Counting Points]](https://codeforces.com/problemset/problem/2074/D)
I remember that I couldn't solve it before... Now it's painfully easy to do, but the idea might be interesting to show in a class or something.
Data structures
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Can be solved with two sets or binary search with sparse table.
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D. Kevin and Competition Memories
Another interesting sparse table problem, I'm not sure it needs one, but I solved with one.
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Another sparse table problem.
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Can be solved with sparse table or coordinate compression with prefix sum.
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Can be solved in two ways, but the sparse table one is interesting, although the other way seems more versatile.
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REALLY good binary search problem, amazing to do and think about, the binary search isn't obvious at all.
Reroot
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Interesting reroot problem, there's not much for me to say about it.
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Very standard reroot problem, but interesting as an exercise.
DP
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It's cool to think about this problem, it has an interesting way to solve.
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D. Inversion Value of a Permutation
Now THIS is a problem you have to think outside the box!
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Interesting LIS problem.
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Knapsack based on weight problem, classic.
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Classic matrix exponentiation problem.
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Amazing knapsack problem, really satisfying to do!
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An interesting way to learn how to visualize a DP as a graph and optmize it using matrix exponentiation.
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A bit basic DP problem, but still interesting to think about all the possible cases and make a DP about it.
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Cool DP problem, you have to understand knapsack to do and optmize it.
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G. Mukhammadali and the Smooth Array
Pretty simple, but requires optmization.
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Basic problem about matrix exponentation, but not as obvious.
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An interesting problem to think about.
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I just liked the problem, not particularly hard.
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Interesting to think about the transitions and the states, although figuring out it's a dp problem is already a challenge by itself.
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Simple dp problem, but it's still interesting to think about it.
Graph
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Cool graph problem, not exactly difficult, but interesting to think about it.
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Amazing graph/dp problem, actually interesting to think about it.
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G2. Medium Demon Problem (hard version)
A very simple problem once you finally understand it, interesting to learn about dfs and all that.
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A really easy problem, at least it is once you realize that it's just a tree and the calculation is simple.
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AMAZING graph problem, I actually had fun solving it.
Math
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E2. Rudolf and Snowflakes (hard version)
Not so hard if you know how to deal with C++ or any other language with big integer, but it's interesting to think about regardless, can also be solved with a binary search, but it's not required.
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Kinda introductory combinatory problem, but interesting as an exercise.
DSU
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https://codeforces.com/problemset/problem/1985/H1
DSU with rollback problem, cool to think about and not really that difficult.
Bridge
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Bridge to compress the graph into a tree.
Divide and Conquer
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Interesting problem to think about, good introduction to divide and conquer in my opinion and can be used as a bridge to segment trees.
String
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G1. Division + LCP (easy version)
Can be solved in a lot of ways, but I find hashing with binary search simpler.