Compilare: user.cpp: In member function ‘char InputReader::nextpos()’: user.cpp:45:42: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, Size, 1, fin); ^ user.cpp: In function ‘void solve(int)’: user.cpp:275:33: warning: ‘cen’ may be used uninitialized in this function [-Wmaybe-uninitialized] for (const auto &i : g[ cen ]) { ^