Compilare: user.cpp: In function ‘int solve(int)’: user.cpp:151:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] ok &= e.size() == n / D; ^ user.cpp:153:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] ok &= it.size() == D - 1; ^ user.cpp:160:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0;i < v[1].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:188:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("divizori2.in","r",stdin); ^ user.cpp:189:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("divizori2.out","w",stdout); ^