# The 15th Birthday

Happy Birthday to me, and many thanks to people who helped me in the past year. Let's keep calm and carry on.

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**2021-09-13 Read more

# Sol: Leo and the MO Problem

Problem Link: http://oj.hecz.info:4000/problem/2 As the problem instructs, you are supposed to solve this function. $$S_n = \sum_{k=1}^{n} \left[ \dfrac{(3k+6)!+1}{3k+7} - \left[ \dfrac{(3k+6)!}{3k+7} \right] \right]$$ Let's take a look at it, cons…

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**2021-08-12 Read more

# The Miller-Rabin Algorithm

Fermat's Little Theorem: For a prime number $p$, for any integer $a$, if $\gcd(a,b)=1$, then $a^{p-1}\equiv1(mod p)$ If you want to judge whether p is a prime number, then randomly x in $[2,p-1]$ every time, if $x^{p-1}\not\equiv1$ then $p$ is not …

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**2021-05-30 Read more

# Hack Submission Results with Python

Front As of the writing of this article, Luogu has accumulated more than 3m submissions. This article uses Python to crawl some submitted samples for subsequent data analysis. Crawl page Luogu's xth submission record, the URL is https://www.luogu…

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**2021-05-20 Read more