Compilare: user.cpp: In function ‘void read()’: user.cpp:18:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=2; i<a.size(); i++) ^ user.cpp: In function ‘void lca()’: user.cpp:37:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<q.size(); i++) ^ user.cpp:46:32: 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:56:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^