Borderou de evaluare (job #810421)

Compilare: main.cpp: In function 'bool valid(std::string)': main.cpp:12:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'unsigned int'} [-Wsign-compare] 12 | for (int i = 2; i < s.size(); i++) { | ~~^~~~~~~~~~ main.cpp: In function 'void backtrack(std::string)': main.cpp:20:18: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'unsigned int'} and 'int' [-Wsign-compare] 20 | if (s.size() == N) { | ~~~~~~~~~^~~~