answer.code:16:8: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   16 | int cn(auto&x,auto y){return x>y?x=y,1:0;}
      |        ^~~~
answer.code:16:15: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   16 | int cn(auto&x,auto y){return x>y?x=y,1:0;}
      |               ^~~~
answer.code:17:8: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   17 | int cx(auto&x,auto y){return x<y?x=y,1:0;}
      |        ^~~~
answer.code:17:15: warning: use of ‘auto’ in parameter declaration only available with ‘-std=c++20’ or ‘-fconcepts’
   17 | int cx(auto&x,auto y){return x<y?x=y,1:0;}
      |               ^~~~
answer.code: In function ‘std::vector<int> ucs(std::vector<int>, std::vector<int>)’:
answer.code:19:45: error: expected primary-expression before ‘{’ token
   19 | ve<int>ucs(ve<int>A,ve<int>B){return A==B?A:{-1};}
      |                                             ^
answer.code:19:45: error: expected ‘;’ before ‘{’ token
   19 | ve<int>ucs(ve<int>A,ve<int>B){return A==B?A:{-1};}
      |                                             ^
      |                                             ;
answer.code:19:48: error: expected ‘;’ before ‘}’ token
   19 | ve<int>ucs(ve<int>A,ve<int>B){return A==B?A:{-1};}
      |                                                ^
      |                                                ;