/in/foo.cc: In function 'int main()':
/in/foo.cc:159:13: warning: variable 'empty' set but not used [-Wunused-but-set-variable]
  159 |         Key empty; empty.lo = 0; empty.hi = 0;
      |             ^~~~~
/in/foo.cc:222:58: warning: 'eids' may be used uninitialized [-Wmaybe-uninitialized]
  222 |                                     int e0 = eids[q][0], e1 = eids[q][1];
      |                                                          ^~
/in/foo.cc:192:33: note: 'eids' declared here
  192 |                             int eids[4][4], en[4];
      |                                 ^~~~
/in/foo.cc:301:29: warning: 'sp' may be used uninitialized [-Wmaybe-uninitialized]
  301 |                     if (sp[n] != 0) continue;
      |                         ~~~~^
/in/foo.cc:299:25: note: 'sp' declared here
  299 |                     int sp[10], si[10], comp;
      |                         ^~