Compilare: user.cpp: In function ‘void dfsA(int)’: user.cpp:17:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v1[node].size(); i++){ ^ user.cpp: In function ‘int dfsB(int, int&, int&)’: user.cpp:28:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i =0 ; i < v2[node].size(); i++){ ^ user.cpp:32:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:35:29: 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:36:31: 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:37:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:40:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&x,&y); ^