Compilare: user.cpp: In member function ‘bool Hash::isIn(std::pair<std::pair<long int, long int>, std::pair<long int, long int> >)’: user.cpp:25:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(long i=0;i<C[id].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:71:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ssdj.in","r",stdin); ^ user.cpp:72:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ssdj.out","w",stdout); ^ user.cpp:76:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&n); ^ user.cpp:77:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1;i<=n;i++) scanf("%s\n",a[i]+1); ^