Compilare: user.cpp: In function ‘void redirectInput(const char*, const char*)’: user.cpp:9: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:10: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void dfs(int, std::vector<std::vector<int, std::allocator<int> >, std::allocator<std::vector<int, std::allocator<int> > > >&, std::vector<bool, std::allocator<bool> >&, std::queue<int, std::deque<int, std::allocator<int> > >&)’: user.cpp:40: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs_based()’: user.cpp:55: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:61: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void Kahn()’: user.cpp:104: warning: comparison between signed and unsigned integer expressions user.cpp:81: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:87: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result