adaptatron's blog

[Video] : Optimizing DP with Segment Trees ft. CF2019D: Speedbreaker
By adaptatron, 2 months ago, In English

I created a video editorial talking about how to use Atcoder Library's Segment Tree to optimize CF2019D: Speedbreaker

https://youtu.be/GyBA_nK4qiw?si=E5qw4X4FLHO5j--_

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2 months ago, # |
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Very hard problems

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    2 months ago, # ^ |
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    I dont get it, D was extremely simple. You just have to track the first and last occursnce of each character, and then keep intersecting the segments.

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2 months ago, # |
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A 20 line implementation would reach $$$O(n)$$$ without segment trees on this problem.

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    2 months ago, # ^ |
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    Yes, I agree Segment Tree might be an overkill for this problem. However, I arrived at the segtree solution without a lot of efforts, hence wanted to share an alternate solution from the editorial.

    Also, looking at submission count of Problem C (6529) vs Problem D (1373), a lot of people did not submit the overkill segtree solution, possibly because they were not aware of such data structures or thought process of reducing the problem to a standard domain, hence the video.

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      2 months ago, # ^ |
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      Yes it's always useful to learn different ways to solve a problem.

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    2 months ago, # ^ |
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    Can you please explain your code and thought process of this problem ?

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