Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:39:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < graph[x].size(); ++i) ^ user.cpp: In function ‘int ancestor(int, int)’: user.cpp:68:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int lca(int, int)’: user.cpp:87:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int way(int, int)’: user.cpp:94:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^