Compilare: main.cpp: In function 'int solve(int, int)': main.cpp:23:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 23 | for ( int i = 0; i < s[k].size(); i++ ) { | ~~^~~~~~~~~~~~~ main.cpp:38:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 38 | for ( int i = 0; i < s[0].size(); i++ ) { | ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:72:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 72 | for ( int j = 0; j < s[i].size(); j++ ) | ~~^~~~~~~~~~~~~