Compilare: user.cpp: In function ‘int first_query(std::string)’: user.cpp:19:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (sol + step < chunk.size() - 16 && chunk.substr (ord[sol + step], Q.size()) < Q) ^ user.cpp: In function ‘int last_query(std::string)’: user.cpp:29:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (sol + step < chunk.size() - 16 && chunk.substr (ord[sol + step], Q.size()) <= Q) ^ user.cpp: In function ‘void radix_sort(int)’: user.cpp:45:22: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized] a[j][++a[j][0]] = ord[i]; ^