Compilare: user.cpp: In function ‘void read()’: user.cpp:19:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=2; i<a.size(); cin >> a[i++]); ^ user.cpp: In function ‘void lca()’: user.cpp:34:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<q.size(); i++) ^ user.cpp:43:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<w.size(); i++) ^ user.cpp: At global scope: user.cpp:53:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^