/in/foo.cc: In function 'void test()':
/in/foo.cc:17:6: error: 'class std::vector<int>' has no member named 'sort'
  ans.sort();
      ^~~~
/in/foo.cc:18:16: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  for(int i=0;i=m;i++)
                ^
/in/foo.cc:16:6: warning: unused variable 'num' [-Wunused-variable]
  int num=ans.size();
      ^~~