/in/foo.cc: In function 'int unique(node*)':
/in/foo.cc:45:6: warning: unused variable 'i' [-Wunused-variable]
  int i=0;
      ^
/in/foo.cc: In function 'node* merge(node*, node*)':
/in/foo.cc:62:6: warning: variable 'tem' set but not used [-Wunused-but-set-variable]
  int tem[10000]={0};
      ^~~
/in/foo.cc: In function 'node* input(int)':
/in/foo.cc:110:9: warning: 'list' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return list;
         ^~~~