P3662 [USACO17FEB] Why Did the Cow Cross the Road II S(前缀和+枚举)
思路：前缀和+枚举（看代码挺好理解滴）ACcode:#includeusingnamespacestd;#defineintlonglongconstintN=1e5+10;intn,b,k,a[N],pre[N];voidsolve(){cin>>n>>k>>b;while(b--){intx;cin>>x;a[x]=1;}for(inti=1;i>t;while(t--){solve();}r