Compilare: user.cpp: In function ‘void bfs(int)’: user.cpp:11:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<g[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:27:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.in","r",stdin); ^ user.cpp:28:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.out","w",stdout); ^ user.cpp:30:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n,&m,&s); ^ user.cpp:33:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^