Compilare: main.cpp: In function 'void solve1()': main.cpp:50:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | for(int i = 0;i < mat.size();i++) { | ~~^~~~~~~~~~~~ main.cpp:57:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 57 | for(int i = 0;i < mat.size();i++) { | ~~^~~~~~~~~~~~ main.cpp:58:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 58 | for(int j = 0;j < mat[i].size();j++) { | ~~^~~~~~~~~~~~~~~