Compilare: main.cpp: In function 'bool check(int, int)': main.cpp:9:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 9 | for (int i = 0; i < words[1].size() - len + 1 and !ok; ++i) { | ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:16:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 16 | for (int k = 0; k < words[j].size() - len + 1 and !found; ++k) { | ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~