Coldfresh的博客

对于求C(n,m) 1.如果是对于小范围内的n和m（不是很难）就不说了 差不多用java的大数就可以了 2.当n在1e10^5范围左右，往往是会有取模，设这个数为mod（往往mod为质数，这个很重要）。 既然是组合数，就免不了有阶乘的部分， n 的范围在10^5的数量级，所以完全可以线性扫一遍，用一个fac数组存i的阶乘对mod取模即可， 但是对于除法取模，必须得用到逆元，所以还是需要去

On the way to the next secret treasure hiding place, the mathematician discovered a cave unknown to the map. The mathematician entered the cave because it is there. Somewhere deep in the cave, she foun

Dashing thro’ the snow, In a one-horse open sleigh, O’er the fields we go, Laughing all the way; Bells on bobtail ring, Making spirits bright; What fun it is to ride and sing A sleighing song t...