Compilare: user.cpp: In function ‘bool bf()’: user.cpp:20:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<cd.size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:44:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.in","r",stdin); ^ user.cpp:45:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.out","w",stdout); ^ user.cpp:46:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:49:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^ user.cpp: In function ‘bool bf()’: user.cpp:27:28: warning: ‘nod’ may be used uninitialized in this function [-Wmaybe-uninitialized] for(j=g[nod].begin();j!=g[nod].end();j++) ^