Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:11:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v2[nod].size();++i) ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:24:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v1[nod].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:53:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<sol[i].size();++j) printf("%d ",sol[i][j]); ^ user.cpp:31:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in","r",stdin); ^ user.cpp:32:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out","w",stdout); ^ user.cpp:33:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:36:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^