/in/foo.cc: In function 'void add(int, ll)':
/in/foo.cc:38:16: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
     if(x=top[x])up[f[x]]+=p*(size[f[x]]-size[x]),x=f[x];
                ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:49:3: error: 'cout' was not declared in this scope
   cout.precision(6);
   ^~~~
/in/foo.cc:57:13: error: 'fixed' was not declared in this scope
       cout<<fixed<<(double)(up[x]+ask(loc[x],0)*c[x]+ask(loc[x],1)*down[x])/down[x]*2<<"\n";;
             ^~~~~