Compilare: main.cpp: In function 'void megold(std::vector<std::vector<int> >&, int)': main.cpp:20:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 20 | while (j < a.size() && x <= a[j][a[j].size() - 1]) | ~~^~~~~~~~~~ main.cpp:24:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 24 | if (j == a.size()) | ~~^~~~~~~~~~~