answer.code: In function ‘void dfs()’:
answer.code:54:44: error: could not convert ‘st.std::set<int>::find(tmp)’ from ‘std::set<int>::iterator’ {aka ‘std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator’} to ‘bool’
   54 |                                 if( st.find(tmp) ) continue ;
      |                                     ~~~~~~~^~~~~
      |                                            |
      |                                            std::set<int>::iterator {aka std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator}
answer.code: In function ‘int main()’:
answer.code:68:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   68 |         scanf( "%d" , &t ) ;
      |         ~~~~~^~~~~~~~~~~~~
answer.code:71:22: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   71 |                 scanf( "%d%d" , &n , &k ) ;
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~