Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:16:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[nod].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:64:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[s].size();++i) ^ user.cpp:50:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.in","r",stdin); ^ user.cpp:51:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.out","w",stdout); ^ user.cpp:54:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&u,&s); ^ user.cpp:56:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i]); ^ user.cpp:59:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^