Compilare: user.cpp: In function ‘std::pair<int, std::vector<int, std::allocator<int> > > solve(graph&, int)’: user.cpp:77: warning: comparison between signed and unsigned integer expressions user.cpp:83: warning: comparison between signed and unsigned integer expressions user.cpp:92: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:122: warning: comparison between signed and unsigned integer expressions user.cpp:102: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:103: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:105: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:108: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:113: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result