foo.cc: In function 'int main()':
foo.cc:15:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     int n, m, k, pos, lo, hi; scanf("%d%d%d", &n, &m, &k);
                               ~~~~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc:21:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d", &pos, &lo, &hi);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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