foo.cc: In function 'int cyl::IO::gi()':
foo.cc:12:17: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   while (c > -1 && c < '0' || c > '9') { if (c == '-') f = -1; c = gc(); }
          ~~~~~~~^~~~~~~~~~
foo.cc: In function 'int cyl::main()':
foo.cc:66:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j = 0; j < D[i].size(); ++j) {
                    ~~^~~~~~~~~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。