hiccup.cpp: In function 'int HicCup(std::string)':
hiccup.cpp:26:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
26 | for (int i=0; i<s.size(); ++i) {
| ~^~~~~~~~~
hiccup.cpp:28:12: error: 'class std::stack<int>' has no member named 'back'
28 | adj[stk.back()].push_back(n2);
| ^~~~
hiccup.cpp:28:30: error: 'n2' was not declared in this scope; did you mean 'n'?
28 | adj[stk.back()].push_back(n2);
| ^~
| n
hiccup.cpp:37:14: error: 'class std::stack<int>' has no member named 'back'
37 | ++cnt[stk.back()];
| ^~~~