摘要： There is an equation ax + by + c = 0. Given a,b,c,x1,x2,y1,y2 you must determine, how many integer roots of this equation are satisfy to the following 阅读全文

摘要： In our daily life we often use 233 to express our feelings. Actually, we may say 2333, 23333, or 233333 … in the same meaning. And here is the questio 阅读全文

摘要： A group of K friends is going to see a movie. However, they are too late to get good tickets, so they are looking for a good way ... 阅读全文

摘要： 欧拉定理表明，若n,a为正整数，且n,a互质，则: 费马小定理: a是不能被质数p整除的正整数，则有a^(p-1) ≡ 1 (mod p) 证明这个定理非常简单，由于p是质数，所以有φ(p) = p-1，代入欧拉定理即可证明。推论：对于任意正整数a，有a^p ≡ a (mod p)，因为a能被p整除 阅读全文