foo.cc: In function 'int main()':
foo.cc:44:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf ("%d%d%d", &n, &m, &kk);
  ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
foo.cc:47:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf ("%d%d%d", &a[i].u, &a[i].v, &a[i].q);
   ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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