Compilare: user.cpp: In function ‘long int flipRow(std::vector<std::vector<int> >&, int)’: user.cpp:6:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < table[row].capacity(); j++) { ~~^~~~~~~~~~~~~~~~~~~~~~~ user.cpp: In function ‘long int flipCol(std::vector<std::vector<int> >&, int)’: user.cpp:16:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < table.capacity(); i++) { ~~^~~~~~~~~~~~~~~~~~ user.cpp: In function ‘bool isValid(std::vector<int>, int)’: user.cpp:25:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (stack.size() >= size + 1) return false; ~~~~~~~~~~~~~^~~~~~~~~~~