Compilare: user.cpp: In function ‘int main()’: user.cpp:21:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(v.size()!=2*n-1) ^ user.cpp:30:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<v.size();i++) ^ user.cpp:12:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("euler.in", "r", stdin); ^ user.cpp:13:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("euler.out", "w", stdout); ^