Compilare: main.cpp: In function 'void preprocess()': main.cpp:13:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 13 | for (int i = 1; i < pat.size(); i++) | ~~^~~~~~~~~~~~ main.cpp: In function 'void match()': main.cpp:25:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 25 | for (int i = 0; i < txt.size(); i++) | ~~^~~~~~~~~~~~ main.cpp:31:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 31 | if (j == pat.size()) | ~~^~~~~~~~~~~~~