Compilare: user.cpp: In function ‘std::pair<int, std::vector<int, std::allocator<int> > > solve(graph&, int)’: user.cpp:76: warning: comparison between signed and unsigned integer expressions user.cpp:82: warning: comparison between signed and unsigned integer expressions user.cpp:90: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:120: warning: comparison between signed and unsigned integer expressions user.cpp:100: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:101: 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 ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:106: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:111: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result