Compilare: main.cpp: In function 'bool solve(int, const std::vector<std::__cxx11::basic_string<char> >&)': main.cpp:29:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < strings.size(); i++) ~~^~~~~~~~~~~~~~~~ main.cpp:43:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < strings[i].size()) ~~^~~~~~~~~~~~~~~~~~~ main.cpp:59:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < strings.size(); i++) ~~^~~~~~~~~~~~~~~~