/in/foo.cc: In function 'int main()':
/in/foo.cc:22:14: warning: unused variable 'k' [-Wunused-variable]
  int n,m,i,j,k,u,v,len,q,a,b,head,tail,ny,sum,top,l,r,mid,ans1,ans2,ci,maxn,last,w,num,jia,shang,zuixiao;
              ^
/in/foo.cc:22:69: warning: unused variable 'ci' [-Wunused-variable]
  int n,m,i,j,k,u,v,len,q,a,b,head,tail,ny,sum,top,l,r,mid,ans1,ans2,ci,maxn,last,w,num,jia,shang,zuixiao;
                                                                     ^~
/in/foo.cc:22:88: warning: unused variable 'jia' [-Wunused-variable]
  int n,m,i,j,k,u,v,len,q,a,b,head,tail,ny,sum,top,l,r,mid,ans1,ans2,ci,maxn,last,w,num,jia,shang,zuixiao;
                                                                                        ^~~
/in/foo.cc:22:92: warning: variable 'shang' set but not used [-Wunused-but-set-variable]
  int n,m,i,j,k,u,v,len,q,a,b,head,tail,ny,sum,top,l,r,mid,ans1,ans2,ci,maxn,last,w,num,jia,shang,zuixiao;
                                                                                            ^~~~~