Compilare: user.cpp: In function ‘void query(int)’: user.cpp:18:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(; step < nr[x].size(); step <<= 1); ^ user.cpp:22:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(p+step <= nr[x].size() && nr[x][p+step-1] <= pos) ^ user.cpp:17:9: warning: unused variable ‘c’ [-Wunused-variable] int c = 0, step = 1, p = 0; ^