Compilare: main.cpp: In function 'int main()': main.cpp:47:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 47 | while (i <= end && k >= v[i].length()) | ~~^~~~~~~~~~~~~~~~ main.cpp:54:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 54 | while (i <= end && k >= v[i].length()) | ~~^~~~~~~~~~~~~~~~ main.cpp:65:39: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 65 | while (i <= end && (k >= v[i].length() || v[i][k] == c)) | ~~^~~~~~~~~~~~~~~~