Compilare: user.cpp: In function ‘void solve(std::vector<thing>&)’: user.cpp:112:9: warning: variable ‘rgt’ set but not used [-Wunused-but-set-variable] int rgt[sz+2], lft[sz+2], st[sz+2], vf = 0; ^~~ user.cpp:112:20: warning: variable ‘lft’ set but not used [-Wunused-but-set-variable] int rgt[sz+2], lft[sz+2], st[sz+2], vf = 0; ^~~ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:18:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^