/in/foo.cc: In function 'void pre()':
/in/foo.cc:35:6: warning: unused variable 't' [-Wunused-variable]
  int t = 1;
      ^
/in/foo.cc: In function 'void debug()':
/in/foo.cc:55:28: warning: format '%d' expects argument of type 'int', but argument 2 has type 'll {aka long long int}' [-Wformat=]
    printf("%d ", f[i][j][k]);
                            ^