The-Winner's blog

By The-Winner, history, 9 months ago, In English

Hello!

I've seen a couple of problems where the intended solution is to use Hall's Marriage Theorem on some weird reduction to solve the problem. These are few and hard to find, so I wanted to ask you for any problems/learning materials regarding this theorem.

One example is IOI-2015/Day1/Teams (although the reduction is fairly natural).

Thank you in advance

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https://www.acmicpc.net/problem/8177

Ice skates is the classic example I know and a really good problem imo

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iirc candies from this year's NOI in Bulgaria uses Hall's theorem.

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JOI Spring Camp Ants and Sugar (sorry on the phone no link)

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https://qoj.ac/problem/6339

Not Hall's Theorem itself, but a similar idea

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    Thank you

    Not sure if it is something on my behalf, but it seems you need to be logged in to see the problem

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https://mirror.codeforces.com/gym/106017/problem/M I haven't coded the solution but my ideas for this problem all come from Hall's theorem.

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Everything listed here;

search query on solved.ac