Compilare: user.cpp: In function ‘void dfs2(int)’: user.cpp:36:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<graph[x].size();i++) ^ user.cpp: In function ‘void dfs(int, int)’: user.cpp:56:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<graph[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:98:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<ans.size();i++) ^ user.cpp:101:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<ans[i].size(); ++j) ^ user.cpp:74:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("clepsidra.in","r",stdin); ^ user.cpp:75:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("clepsidra.out","w",stdout); ^ user.cpp:77:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:80:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^