Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:14:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < v[nod].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:22:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("in.in","r",stdin); ^ user.cpp:23:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("out.out","w",stdout); ^ user.cpp:24:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:26:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^