Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:12:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < a[nod].size() ; i++) ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:26:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < a[nod].size() ; i++) ^ user.cpp: In function ‘bool comparator(std::pair<int, int>, std::pair<int, int>)’: user.cpp:47:1: warning: control reaches end of non-void function [-Wreturn-type] } ^