CodeForces #315 (div1) B.Symmetric and Transitive
题目大意:不懂。解题思路:没有,至今不会。当时能过的原因是群里有人说是贝尔数,然后一顿乱搞。#include
#definemod1000000007
#defineLLlonglong
usingnamespacestd;
longlongB[4001],c[4001][4001],n,ans=0;
intmain(){
while(scanf("%d",&n)!=EOF){
for(inti=