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欧几里德算法欧几里德算法又称辗转相除法，用于计算两个整数a,b的最大公约数。gcd函数就是用来求(a,b)的最大公约数的。 gcd函数的基本性质：性质一：gcd(a,b)=gcd(b,a)=gcd(-a,b)=gcd(|a|,|b|)证明略。 性质二：gcd(a,b)=gcd(b,a mod b)证明：a可以表示成a = kb + r

DescriptionChinachen is a football fanatic, and his favorite football club is Juventus fc. In order to buy a ticket of Juv, he finds a part-time job in Professor Qu's lab.And now, Chinachen have

乘法逆元定义：满足a*k≡1 (mod p)的k值就是a关于p的乘法逆元。为什么要有乘法逆元呢？当我们要求（a/b） mod p的值，且a很大，无法直接求得a/b的值时，我们就要用到乘法逆元。我们可以通过求b关于p的乘法逆元k，将a乘上k再模p，即(a*k) mod p。其结果与(a/b) mod p等价。证：（其实很简单。。。）根据b*k≡1 (mod p

Mr. Miyamoto is playing with a wheel. Each wheel can have many spokes. A spoke is one of the rods radiating from the center of a wheel (the hub where the axle connects), connecting the hub with the ro