Compilare: user.cpp: In function ‘bool check(int)’: user.cpp:131:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<G[p].size();i++) ^ user.cpp: In function ‘void read()’: user.cpp:109:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("transport2.in","r",stdin); ^ user.cpp:110:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:113:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&z); ^