xylophone.cpp: In function 'void solve(int)':
xylophone.cpp:21:18: error: 'struct std::pair<__gnu_cxx::__normal_iterator<int*, std::vector<int> >, __gnu_cxx::__normal_iterator<int*, std::vector<int> > >' has no member named 'fi'
bool flip = it.fi < it.se;
^~
xylophone.cpp:21:26: error: 'struct std::pair<__gnu_cxx::__normal_iterator<int*, std::vector<int> >, __gnu_cxx::__normal_iterator<int*, std::vector<int> > >' has no member named 'se'
bool flip = it.fi < it.se;
^~
xylophone.cpp:22:16: error: 'struct std::pair<__gnu_cxx::__normal_iterator<int*, std::vector<int> >, __gnu_cxx::__normal_iterator<int*, std::vector<int> > >' has no member named 'fi'
int mi = *it.fi;
^~