Eiffel的博客

Combinations  Given n different objects, you want to take k of them. How many ways to can do it? For example, say there are 4 items; you want to take 2 of them. So, you can do it 6 ways. Take 1,

Lucas定理是用来求解C(m,n)mod p的值的。其中m和n的值可以很大，p一定是素数。 对阶乘打表的模板 LL quick_mod(LL a, LL b, LL c)//费马小定理+快速幂求逆元 { LL ans = 1; while (b) { if (b%2==1) ans = (ans*a) %

E. Devu and Flowers time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output Devu wants to decorate his garden with