Compilare: user.cpp: In function ‘int solve(std::vector<int>&)’: user.cpp:44:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i<v.size(); ++i){ ^ user.cpp: In function ‘int main()’: user.cpp:58:20: warning: unused variable ‘a’ [-Wunused-variable] for(int i = 1, a, b; i<=n; ++i) ^ user.cpp:58:23: warning: unused variable ‘b’ [-Wunused-variable] for(int i = 1, a, b; i<=n; ++i) ^