Compilare: user.cpp: In function ‘int main()’: user.cpp:20:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[0].size();i++) ^ user.cpp:21:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i+1;j<v[0].size();j++) ^ user.cpp:24:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[1].size();i++) ^ user.cpp:25:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i+1;j<v[1].size();j++) ^ user.cpp:30:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<edges.size(); i++) ^ user.cpp:11:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fenrir.in", "r", stdin); ^ user.cpp:12:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fenrir.out", "w", stdout); ^