Compilare: user.cpp: In function ‘int dfs(int)’: user.cpp:14:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[k].size(); i++) ^ user.cpp: In function ‘int dfs2(int)’: user.cpp:34:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[k].size(); i++) ^ user.cpp:42:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:48:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pm2.in", "r", stdin); ^ user.cpp:49:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pm2.out", "w", stdout); ^