Compilare: main.cpp: In function 'void solve()': main.cpp:54:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 54 | for (int j = 0; j < v[i - 1].size(); j++) | ~~^~~~~~~~~~~~~~~~~ main.cpp:61:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 61 | for (int j = 0; j < v[r].size(); j++) | ~~^~~~~~~~~~~~~ main.cpp:75:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 75 | for (int j = 0; j < v[i + 1].size(); j++) | ~~^~~~~~~~~~~~~~~~~ main.cpp:82:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 82 | for (int j = 0; j < v[l].size(); j++) | ~~^~~~~~~~~~~~~