Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:13:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[k].size();i++) ^ user.cpp: In function ‘void rmq()’: user.cpp:27:15: warning: suggest parentheses around ‘-’ inside ‘<<’ [-Wparentheses] x=1<<i-1; ^ user.cpp: In function ‘int main()’: user.cpp:47:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lca.in","r",stdin); ^ 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("lca.out","w",stdout); ^ user.cpp:50:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:53:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^ user.cpp:68:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^