Compilare: user.cpp: In function ‘bool is_next(std::vector<std::vector<int> >&, int, int)’: user.cpp:16:31: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] ad[current].size() == 1 && ad[current][0] == last); ^ user.cpp: In function ‘int main()’: user.cpp:20:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("socks.in", "r", stdin); ^ user.cpp:21:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("socks.out", "w", stdout); ^