Compilare: user.cpp: In constructor ‘TwoSAT::TwoSAT(int)’: user.cpp:25:6: warning: ‘TwoSAT::n’ will be initialized after [-Wreorder] int n; ^ user.cpp:20:22: warning: ‘std::vector<std::vector<int> > TwoSAT::G’ [-Wreorder] vector<vector<int>> G, G_T; ^ user.cpp:27:2: warning: when initialized here [-Wreorder] TwoSAT(int n) : n(n), G(2 * n), G_T(2 * n), Viz(2 * n), ^ user.cpp: In member function ‘void TwoSAT::dfs_backward(int)’: user.cpp:55:25: warning: suggest parentheses around arithmetic in operand of ‘^’ [-Wparentheses] Sol[node / 2] = (node & 1 ^ 1); ^ user.cpp: In function ‘int main()’: user.cpp:80:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("2sat.in", "r", stdin); ^ user.cpp:81:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("2sat.out", "w", stdout); ^