Compilare: user.cpp:25:24: warning: integer overflow in expression [-Woverflow] const int oo = (1<<31)-1; ^ user.cpp: In function ‘int main()’: user.cpp:92:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < X.size() - 1 ; ++ i) ^ user.cpp:94:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < X.size() - 1 ; ++ i) ^